Part 2: Game Mechanics Megadump -- go here if you're confused!

OGRE BATTLE 64 GAME MECHANICS MEGADUMP
This humongous wall of text describes more or less the system of the entire game. If at any point you are confused by something that is happening in an update, refer back to this and it should clear right up! (WARNING: screenshots in this post from GIS)

UNITS AND COMBAT
FORMATION

-A unit is a 3x3 grid -- three rows (front/middle/back) and three columns (left/center/right). Each square on the grid can contain one unit. Large characters (some monsters) must have an empty buffer of one square between them and anything else.
-Which row you are in affects what actions you take and how many of them you get per battle -- melee attackers mostly want to be in the front, while ranged attackers mostly want to be in the back. Classes that are any good in the middle row are few and far between, but there are a few that do just fine there.
-Which column you are in affects what enemy characters you can target -- you can only attack characters in the column across from you, or one column to the left or right. This means that if you're in the left column, you can't hit anything that's all the way over on the right unless there's no other option. Naturally if all the enemies in the left and center columns are dead, you can start hitting stuff on the right, but not until then. Characters in the center column are free agents, attacking any column they please, but they're also huge targets since any column can attack them right back.
-Your row and column together decide what kinds of attacks can target you. If there is someone in your column in front of you, any melee attacks have to go through them first (meatshields that aren't directly in front of you do you no good); if there is anyone in your column behind you, ranged (magic/archery) attacks have to get rid of them before they can hit you. Hence, the safest place for a character to be is in the middle row, in the left or right column, behind a character with good physical defense (like a phalanx) and in front of a character with good magic defense (like a Sorceress). This isn't perfect, of course, since Archers have a ranged physical attack perfect for mowing down mages, but those are relatively rare compared to caster characters.
BATTLE

- Every character, depending on his/her position, gets between 1 and (in the most extreme cases of gamebreaking) 4 attacks. Once every character on both sides of a battle finishes all of his/her actions, the fight is over, no matter what, and (in most cases) whichever side dealt more damage is said to have won. You also win if you wipe out the other side completely. The losing unit will give ground after the battle is over. Unless they're all dead.
-Attack order is determined by each character's Agility. Characters in the front go first. If you are disabled or (of course) dead during a point in time when you would otherwise attack, you get no action.
-Physical attacks (melee/archery) have a chance to be blocked (by heavy-armor characters) or dodged (by light-armor characters), but they also have a chance to deal Critical hits. A crit will deal extra damage and will push the target a row back in formation unless there's already something there. This will not affect what type of action that unit will take in future unless you are in a training battle. Magic attacks cannot deal critical hits, but even if they are dodged/blocked they are guaranteed to do some damage. They can also deal splash damage if high enough level and be combined in various ways -- more on that later.
-In special battles (mission bosses), the battle is won if and only if the opposing leader is killed. If you run out of actions and that boss is still standing, you lose, no matter how much you beat up everyone else. Of course this isn't the worst thing in the world. Send someone back in before he heals up too much and you're fine.
-Characters that are dead get carried around by their unit-mates until you revive them (via a Witch Den or using an Altar of Resurrection) or they get so rotten and gross that they turn into a zombie (more on that at some undetermined point in the future). Death is impermanent, but zombification is forever. There is a third possibility besides revival and zombification, but I choose not to discuss it here just yet.
-If a unit's leader dies, that unit is a sitting duck that will ignore all orders and run away from all impending combat. You can get around this in your units by assigning a new leader (if the unit contains any more eligible characters), but the AI cannot. Expect this to get exploited pretty much constantly.
-If a friendly unit is wiped out, it will disappear from the field map. Don't expect this to ever, ever happen.
-The only action that you, the player, can take during battle is Interrupt Commands. What you can do is determined by the Interrupt Meter, which fills slowly based how much total damage has been dealt by both sides, as well as how much time has passed. You can change your unit's Battle Strategy (which determines what characters they target) more or less whenever you want; eventually you can order your unit to Retreat (which counts as an instant loss), and if a battle drags on long enough, you can use an Elem Pedra (a bonus attack which we'll see once I start using them). Taking any action will empty the Interrupt Meter, so if you're almost able to use a Pedra, now is probably not the best time to change your Battle Strategy.
-Possible battle strategies: Autonomous (every unit just picks a valid target at random and attacks it); Attack Weakest (of your valid targets, you hit the one with the lowest HP); Attack Strongest (the opposite of Attack Weakest); Attack Leader (if you can hit the enemy leader, you do; otherwise you act Autonomously). Attack Leader is far and away the most useful; I'll be using it almost all the time.

STRONGHOLDS AND MARCHING

-Every mission takes place in an area roughly the size of a county (with a few exceptions). The map of this area consists of strongholds (which can be castles, forts, or towns of a few dozen or hundred people) and the vast space between them. In most missions, one stronghold is your HQ and one is the enemy HQ. Almost all the time, the mission boss will be unable to leave his/her HQ; if you defeat the boss (and claim his/her HQ) you win the mission, but if your HQ falls (or the main character dies) you lose and it's Game Over.
-If a friendly unit and an enemy unit get too close, they'll enter battle. If one (or both) of them is facing the wrong way when this happens, they will enter battle with their formation all sideways or backwards. You don't want this to happen to you; suddenly your casters will be tanking for your frontliners and everything will get fewer attacks. It's possible to set up formations so that facing a different way will never have too bad an effect on them, but this is mostly unnecessary as long as you're on top of your shit, and the result will never be optimized.
-You can only see (and target) enemy units that one of your units can see. How far a unit can see is a function of where it is and which way it is facing. Units will usually (unless they're marching) automatically face any enemy that gets too close, which is annoying when you actually want them to face some other way and have to keep telling them to spin around over and over.
-Terrain affects the marching speed (and pathfinding, since the algorithm is designed to maximize marching speed) of units crossing it. Most characters walk best on Roads, followed by Grassland, followed by everything else. Some characters are rated to walk just fine on barrens/mountains or forests or snow; some units fly and ignore all terrain. A unit's terrain rating is only as good as the worst-rated character in it: if your unit is comprised of four flying units and one Wizard, for example, the fliers will have to wait for the Wizard to haul his hobbly old ass around everywhere. They can't carry him.
-Speaking of flying units, anything that can fly moves very quickly on the map, but gets tired quickly. More on fatigue in a second.
-Rivers are impassable unless your unit is all fliers or you are crossing a bridge. This makes tracking down leaderless flying units a huge pain in the ass occasionally.
-Give a unit some marching orders and it'll start marching. You can tell them to walk to a Location, take a Stronghold, or track down an enemy Unit. Pathfinding is mostly pretty good, but there are some annoying parts. The longer a unit schleps around, the more Fatigue it accumulates. Tired units fight poorly. You regain fatigue by hanging out in a Stronghold or by Camping. If a unit's Fatigue meter fills all the way up, it must immediately drop what it's doing and start Camping. When Camping your units cannot move but slowly regain Fatigue and health. Make sure your Camping units don't get attacked, though, or they'll all start the battle with the Sleep debuff!
-Defending a Stronghold gives units a slight battle advantage (WARNING: hearsay; I'm not actually quantifiably sure of that) and damaged characters will slowly regain health when not in battle if their units are on a Stronghold. If your characters enter an enemy or neutral Stronghold, they will automatically capture/liberate it. You cannot enter a Stronghold containing enemy troops until you drive them all out.

LEGIONS

-Legions are basically an organizational tool. I guess the designers of OB64 figured you might get tired of ordering five units to go to this town and the other five to go to that town again and again, so to save time you can organize them into a Legion which is basically a meta-Unit.
-Legions obey orders like one Unit and can march around in a number of different formations. The formations may be changed on the fly.
-Only certain characters are capable of leading Legions. Those can be either Centurions (a special class I'll get to later) or characters of certain unique classes we'll get access to after Chapter 2 ends.
-In addition, the Legion Leader's unit must include at least one group of Soldiers to act as messengers or whatever shit. Yes. Soldiers. In Chapter 2 and onward.
-Whenever a unit that is not the Legion Leader's unit gets in a fight, the Soldiers in the Legion Leader's unit get to make one bonus cameo attack on all enemies. This is not enough damage to matter in the slightest, MAYBE unless the leading unit has 4 groups of soldiers. This of course makes at least one terrible unit in your legion.
-That's a bad thing because if your legion leader dies, no more legion. It disbands and turns into a bunch of single Units. Or wait maybe that's a good thing. I dunno man fuck Legions. At any rate, this is why you want to attack the leader unit of enemy Legions last, because when they break up, all the other units will start doing their own thing, which probably means all bumrushing whatever unit just killed the leader, since it'll be closest. Much better to have the initiative yourself.
-There are pretty much two reasons to make a Legion: (1) Looking for items on the ground if you don't know where they are and want to cover a whole lot of ground at once, and (2) looking for Neutral Encounters without having to give orders to all your units and hear them all say they're camping or waking up or need MORE orders OVER AND OVER AND OVER GAH.

CHARACTERS
Your characters can come in one of four major flavors: Men, Women, Demi-humans, and Monsters of various types. There are a couple of offshoot types, mostly spoilery, but those are the big four.

Non-human characters
Demi-humans and monsters can be encountered on the field map as Neutral Encounters; by default you fight them, but you have the option to try to recruit them into your battalion. It may or may not work -- they'll either join up, get a free attack, or run away. If they flee, you get bupkis. If you kill them, you'll get some kind of item as a reward (usually fairly worthless).

Monster units are kind of like Pokemon: they have one class, cannot be switched, and, if they meet the correct level/stat/alignment criteria or are affected by certain events, can evolve into more powerful forms. For example, if a Hellhound gets strong and Chaotic enough, it can sprout a third head and become a Cerberus. If a Golem is petrified, it becomes a Stone Golem; if a Stone Golem gets hit with a combo Fire/Wind elemental attack, it becomes a Baldr Golem.
Wyrm

I don't like Wyrms. They can fly, but they're definitely not better than two regular-sized units, meaning it's not worth giving up two slots for their fat asses. Decent attackers, but I'd rather have two normal characters than one of these things any day. Oh, and as Beast units they get stronger when in a unit led by a Beast Tamer, but Beast Tamers can't fly, which kind of ruins the point of using a Wyrm. Not my favorite beast. Two attacks in the front row, one everywhere else.
Hellhound

I love these things. Big, tough, powerful, Chaotic, and one of the first units you can get access to that gets 3 attacks in the front row. They kick like a mule, have decent HP (to compensate for the fact that they have no armor), dodge attacks reasonably well, and mesh very well with Beast Tamers. You want to keep Hellhounds in the front row, and if an enemy unit has one, try to attack it from a direction that'll keep the Hellhound in back. 3 attacks in the front row, 2 in the middle, one in the back.
Griffin

Roughly equivalent to the Wyrm. Mid-range flying attacker; Large size. Gets two physical attacks in the front; gets two wind-element magic attacks in the back. Neither are particularly strong. One physical attack in the middle. I'll never use these either.
Golem

Huge animated clay man from Hebrew mythology. In OB64, Golems are best described as "big palooka." They're quite resistant to being hit or stabbed with things. Their weaknesses include magic (particularly Lightning) and being blocked due to their low Dex. This last one is lessened slightly by being placed in a unit led by a Doll Master, which makes them worth using. 3 attacks in the front row; 2 in the middle; 1 in the back.
Stone Golem

This is what happens when a Golem gets petrified. Since units that cause the Petrification status are very rarely used by the AI, and it's not possible to do it yourself through friendly fire, it's much easier to just catch some in the wild as soon as you can. They're basically Golems but more so, with some more physical might thrown in there.
Baldr Golem

The third tier Golem unit, they just sort of skipped from "clay" to "rock" to "MAGICAL METAL." Note that Baldr is bright green in this instance and in Baldr Shields, but in no other circumstances. Yeah I dunno. Anyway the way you get one of these things is to have a Stone Golem get hit with a combo Wind/Fire magic attack and survive. Yes. NOTE: Have you seen AI mages use ANY combo magic as yet in this LP, let alone that particular combination of elements? (No, you have not.) Much, much easier to catch new ones than to make your own.
Mature Dragon

Yet another Large frontliner character. These things get different sprites and back-row attacks based on their innate element (or alignment if it's extreme in one direction or the other). Two bites in the front row, one in the middle, and a <Element> Breath attack in the rear. Get a bonus if led by a Dragon Tamer. They're ok for now, but they start getting awesome in their next iteration.
Cerberus

The upgraded Hellhound, and just as useful in mid-game as those were in early-game! Three attacks in front, still, and they also gain a unique back-row attack called Mesmerize which deals Dark damage, with splash and a chance to cause Sleep (which also splashes). Mesmerize is useful and everything, but I still like having these things in the front row better. They'll take your goddamn head off.
Opinincus

The advanced Griffin, with a name that is annoying as HELL to type. I always end up with either Opininincus or Opinicus. Anyway Griffins are boring and so are opininci. They do get a target-all attack from the back row, but it doesn't deal good damage or have a chance to cause status, so I remain unimpressed.
Venerable Dragon
When you level a Mature Dragon enough, it stops being mundanely badass and starts being legendarily badass. Depending on what element Mature Dragon it is, it will become a different type of Venerable Dragon. They get two elemental breath attacks in the front row, which is okay, but in the back row they get huge spells that hit all enemies and have a chance to cause status (in, yes, ALL enemies). I'll probably post art and (shorter) writeups for each individual flavor, because they look MUCH more distinct from each other than the Mature Dragons do.
Tiamat

Big nasty-looking Bane-element piece of work. Its back-row attack, Evil Dead, has a chance to put all enemies to sleep (if you can give me a shot where you successfully put ALL enemies to sleep with a single Evil Dead, though, I will turn over all LP duties to you immediately (this will not happen)).
Flarebrass

Come ON guys. It's a FIRE DRAGON, you couldn't think up a better name for it? All the other Venerable Dragons have names that are references to something from some mythology or other except this one which is a word they made up. At any rate its back row attack Crimson Note has a chance of inflicting Power Down.
Bahamut

The fully-evolved Platinum Dragon, and a pretty good source of Virtue damage. Their back-row spell, Divine Ray, doesn't cause status (to my knowledge) but it's still a good counter for Undead due to spreading a lot of Virtue damage around over all enemies.
Quetzalcoatl

The Wind-flavored Venerable Dragon. In the back row, uses the Radiant Gale attack, which does the usual amount of damage and has a chance to inflict Paralyze. One of the better ones.
Hydra

The Water-element Venerable Dragon. One of my personal favorites. Uses the awesomely-named, fabulously-animated attack Clear Disaster from the back row, which has a chance to put targets to sleep.
Ahzi Dahaka

The Earth-element Venerable Dragon and my personal favorite. Its back-row attack, Earthquake, is unique in that it is 100% guaranteed to cause a Power Down in every single character it hits. Power Down isn't the best status, but being guaranteed to put it on every single character in the opposing unit more than makes up for that. Of course, there is one serious weakness-- Earthquake is completely ineffective against flying targets. Plan accordingly.

Demi-humans are guys with wings. They are fast and can fly over obstacles, but tire out quickly. Some of them (Hawkmen) can be switched around between a few (mostly interchangeable) classes; others are basically Monsters that only take up one character slot.
Hawkman

The basic Flying character class: ignores terrain, flies over rivers, goes really fast, gets tired really fast. Not great stats-wise, and can't lead its own unit, but can change into better classes that neither of those apply to. Not a whole lot else to say about them. Two attacks in the front, one everywhere else.
Raven

Quoth the Raven, "I am a standard upgrade to the basic Hawkman class of Chaotic to Neutral alignment." Can lead a Unit; has a fairly good back-row attack called Thunder Arrow and hits for a decent amount from the front. Really pretty decent in either slot. I personally favor them slightly over their Lawful counterpart, but they're pretty interchangeable.
Vultan

The standard Lawful Hawkman upgrade. Faster than Ravens; less Dexterity than them, though, which makes them not as good in the back row. Pretty much exactly interchangeable with them in all other ways. Two attacks in the front; one in the middle; two Wind Shots in the back. That's the same magic attack Griffins get in the back. They're not very good at it either.
Gremlin

I hate these things. Small, annoying, chaotic, hard to hit. In the front two rows, they attack with Blow Kiss, which gives a Power Down debuff, making them even HARDER to hit. In the back row, they get an Abyss attack, which has a chance to put targets to sleep. None of this has any damage output to speak of, making them kind of useless in your own units, but killing them is a HUGE pain in the ass.
Faerie

The Gremlin's Lawful, more useless cousin. In the front two rows, the Faerie gets a similar Throw Kiss, but rather than being a hostile debuff, it's a friendly buff that heals a couple of HP and grants a Power UP status. The thing is, the fairy's AI treats this like a regular heal and targets whichever ally is shortest on HP, be that ally a Witch, a Cleric, or a Soldier who's already done attacking. In the back row, it gets Magic Missile, which deals Holy-element damage. This would be useful if it wasn't pretty much the weakest attack in the game.
Pumpkinheads

These things are gimmicky, but the thing is that I really like their gimmick. Their main attack, Pumpkin Smash, will halve the HP of its target. In other words, this thing starts combat off by wrecking shit, then sees diminishing returns. Still pretty awesome, if something of a glass cannon. Their back-row attack is something else again, but I decline to explain it here. (Please humor me and follow this example!)

DEMONS
These things show up a lot as enemies -- we'll be able to recruit some of them ourselves, but not for a while. It is widely rumored that doing so deals a blow to one's Chaos Frame, but (of course) no one can really prove it.
Ogre

In two words: HUGE MOTHERFUCKER. Has the attack of a Hellhound, the defense of a Golem, and the HP of a glacier. These things are bad news. Three attacks in the front row, two in the middle, one in the back. They are pretty slow, though, so enemies have a decent chance of blocking or dodging those Fighter-sized hammers. Magic works well too.
Goblin

These guys aren't really worth your attention. Often seen with Ogres, but really the Ogres are the things you should be worrying about. Not terrible, but not anything to write home about either. Two attacks in front, one everywhere else.

Human characters
Humans must be either recruited (if unique) or promoted from Soldiers (if generic). Which classes you can take as a human depend on your sex -- OB64 is a shameless enforcer of the gender binary and of gender stereotypes. A character raised for 30 levels as a Wizard can have an epiphany and suddenly decide to become a Barbarian, but a woman in OB64 can never become a Knight, no matter how strong and brave she is, and a man can never become an Archer, no matter how keen his eye. Tragic, I know. Blame Japan.

Soldiers

These little guys are as generic and expendable as you get. You get a certain number of them after every mission; they can only fight in groups of three. They are nameless and androgynous. A set of three soldiers counts as one character; if it takes enough damage, one of them will die. If a soldier dies, it's no big deal; you've got dozens more, just grab another one from the big pile. They're almost completely worthless, though. Their tiny little spears do almost no damage, and they only get to attack once per battle. If multiple groups of Soldiers positioned in the same row attack the same target at the same time, they can swarm the target and attack simultaneously for a damage bonus; this is nice but doesn't make much difference in the end. Once a unit with Soldiers in it gets enough victories in real battle (not training), one of the Soldiers can earn their own name and get promoted to a full unit of the same sex as the unit's leader (or the opposite if the unit is carrying an Ansate Cross). This happens faster in units with more soldiers, but those are of course less likely to get victories in real battle. Because soldiers suck. Unfortunately they're a necessary evil if you ever want to get anything better.

Centurion

The two best words to describe Centurions are the same two best words to describe Legions: "meh" and "not worth the effort." These things aren't BAD, but in order to qualify as a Centurion a unit leader (male OR female) must promote 7 soldiers. Remember how long it took me to get rid of my soldiers? Yeah, no single leader ever promoted more than three. I can only imagine how long it would have taken me to do seven. At any rate, this is the only generic class that can lead a Legion. If you really want a Legion, though, seriously just use a special character and save yourself the hassle.

Men
Men in OB64 are mostly meatshields and sword-swingers. They make good frontline fighters but suffer from the drawback of many classes being roughly interchangeable melee-attacker units. You could get away with making all of your male characters Knights/Paladins and do pretty damn well (but that, of course, would be SNOOZEFEST '11).
Fighter

Once a Soldier in a unit with a male leader gets promoted, he becomes a Fighter. Fighters are a starter class; the only purpose of the class is to get the stats to turn into something better. Generic and largely incompetent frontliner. Two melee attacks in the front row, only one anywhere else. Cannot be made into Unit Leaders.
Knight

I like Knights. These guys are the basic Lawful frontliner unit for the first portion of the game; they've got good attack and good armor. Very well-rounded. If they have one downside it's that their equipment is on the expensive side, but this is (of course) not a big deal at all. The vast majority of male characters not meant to serve another specific purpose will be made into these guys.
Wizard

Turn a guy into a Wizard, he ages 50 years. Turn him back, he gets young again. I dunno man. Anyway this is the basic male magic-using class. Poor physical defense, good magic defense, etc etc. Better Intelligence than the female equivalent, the Sorceress, but worse Mentality. Blame Japan for that, but basically it means that Wizards have better offense and Sorceresses have better defense. This guy is the only basic male ranged attacker. Magic is pretty good in this game; for most of the early- and mid-game you want them in groups of two because they can work together that way! Two attacks in the back row, one everywhere else.
Berserker

The basic Chaotic melee unit. A guy with an axe and with very little armor. Good attack, good toughness to make up for the armor thing. Not great on MDef, but hey, he's a frontliner. Put one of these guys in front of your Wizards and Sorceresses in your Chaotic units. Two attacks in the front row, one everywhere else.
Ninja

The stat requirements for being a Ninja are pretty low, and they're the only human class other than Fighters and Amazons (and  undead ) that are incapable of leading a unit. This might fool many players (myself included) into thinking that they are basically a slightly faster Fighter. Thing is, in terms of stat growth they're actually roughly equivalent to the Knight, just with less HP and more AGI. This makes them a perfectly serviceable Chaotic frontliner (their weapons, Claws, are pretty rare but that's about the only problem). Just find someone else to actually lead your unit.
Doll Master

Sort of a Neutral equivalent to the Beast Tamer. Well-rounded in terms of stat growth, but its points in INT would probably be better spent in STR or VIT since it is after all a melee attacker. Notable for three things: (1) two attacks in the middle row (also one in the back and two in the front); (2) as Unit Leader, gives a bonus to any Golems in its unit; (3) its weapon is a goddamn marionette that it makes come to life. Yeah.
Phalanx

The tankiest of tanks. A neutral, Spear-wielding, shield-carrying, heavy-armor-wearing melee attacker with good defense and fair-to-middling offensive capability. They're pretty good at not dying, but then ideally ALL your characters should be. Generally it's more important for your units to be good at cracking heads than it is for them to be able to take a beatin', but Phalanxes have their uses.
Black Knight

The advanced Berserker class. I'm still not exactly sure how that follows, but whatev. These guys are pretty much the best Chaotic frontliner unit give or take. Pros: GIANT Strength growth, on par with a Beast unit. Cons: Only get two attacks in the front row; most other (male) advanced melee classes get three. Also the number of them you can make is limited because one of their required items, the Valiant Mantle, is not available in any store. Two attacks in the front and middle, two magics in the back if you're into that.
Paladin

Yeah I'm pretty sure these guys are my favorite non-special class in the game. They're the gold standard frontliner class. The advanced Knight, pure Lawful, these guys come standard with a Blessed Sword and Baldr Armor, get pretty damn good stat growth, and attack three times from the front row. (Two in the middle, two magics in the back.) If you have a Lawful unit that doesn't have at least one of these guys in the front, it's probably because you have tons of them in other units and are sick of them.
Ninja Master

The other major Chaotic advanced frontliner besides Black Knight. Balanced in both the front and the back -- their Ninja Art attack from the back row will hit with some area magic spell that seems to be unrelated to the innate Element of the character. Not quite sure how it's determined. Their STR growth isn't great, but they'll do in a pinch if you run out of Black Knights, especially since they get 3 attacks in the front row.
Beast Master

The advanced form of the Beast Tamer, the Beast Master is a pretty cool old guy and an okay fighter. His primary use is leading a Beast unit, naturally; he's a bit poor on defense, though, so put him behind something big and snarly. Two attacks from anydangplace.
Archmage

This guy's an upgraded Wizard. You can probably tell by the beard. In the back row, he gets to cast tier-2 magic, which either deals intermediate damage to an area or heavy damage to one unit with splash. In combos, they can cast spells on all enemies!
Enchanter

These guys are pretty cool. They're the advanced Doll Master class, they have pretty much the most well-rounded stat gains in the game (second perhaps to Valkyries and their advanced class), and for some unfathomable reason they get three attacks in the front row (two everywhere else). Not entirely sure why you'd put one there, especially since "well-rounded" means "not particuarly optimized for melee combat," but the option's there!
Cataphract

Like a Phalanx but more so. Bigger, tougher, with a larger shield; still pretty unimpressive offensively. They make good bodyguards in units with a heavy back-row payload, but honestly the other frontliner classes perform passably in that role while actually contributing on offense. These guys ARE pretty visually imposing, though. Two attacks in every row.
Sword Master

This guy is basically the Highlander. He's an awesome old Scottish dude with a claymore and he'll kick your goddamn ass. I do wish they'd made his kilt a little bit more plaid, but what are you gonna do? Anyway the Sword Master, like the Fencer before him, is a bit of a glass cannon. He'll wreck some shit, but be careful about how much damage he's taking, he's old! Three attacks in the front, two in the middle; in the back he gets something called a Sonic Boom which hits the back row for physical damage, but also hurts the Sword Master, and doesn't really deal enough damage to be worth that. Pass. Put him in the front.

Women
Women in OB64 are more specialized (meaning less generic) units than men -- only two class lines can reliably be used as frontline fighters, and of those only one doesn't have a gimmick. The drawback to using women is that none of them can wear heavy armor or attack via melee 3 times in a battle. Each of them fills a unique role, though -- on the whole, they're better designed than the male classes are.
Amazon

Once a Soldier in a unit with a female leader gets promoted, she becomes an Amazon. Where Fighters are generic and largely incompetent frontliners, Amazons are generic and largely incompetent back-row archers. Only use Amazons until you get the stats to turn into something better. Two ranged attacks in the back row, only one anywhere else. Cannot be made into Unit Leaders.
Dragon Tamer

One of two female classes useful as frontline fighters. As you can probably tell from their name, they're good with dragons -- if you can manage to recruit a dragon, and stick it in a unit led by a Dragon Tamer, that dragon will fight harder. The Dragon Tamer wears a dragon skull on her head; that's how she keeps the things in line. Two attacks in the front, 1 everywhere else.
Witch

Aside from looking like they're dressed for a college Halloween party, witches are as gimmicky as gimmicky gets. They don't actually attack; instead they inflict status ailments. Status ailments only last as long as the battle you're fighting. I'd rather deal damage any day of the week. Two, uh, "attacks" in the back row, one everywhere else.
Valkyrie

The other female frontliner class besides Dragon Tamer, Valkyries have slightly better armor options but slightly worse stat growth (and no Dragon bonus). When placed in the back row, they use a magic attack (always Lightning, regardless of innate element) if that's your thing (it's not mine). Very well-rounded class; questionable choice of headwear. Two stabs in the front, one in the middle. One Lightning in the back.
Sorceress

The basic female offensive chaotic spellcaster. Gets two magic attacks (determined by innate element) in the back row and one everywhere else. Slightly more defensively oriented in stat growth than their male counterparts, and more visually interesting due to being less cliched. I think her collar is popped all the way off her body.
Archer

If the Knight can be seen as an upgraded Fighter, the Archer is an upgraded Amazon. Ranged physical attacks are excellent for harassing enemy mages and clerics, and the Archer line is the only place to get them! In addition to being stronger, faster, tougher, and all around better than the Amazon, the Archer gets two attacks in the middle row and is unique in that she's actually strongest there -- physical attacks always get stronger the further forward you are, although of course the Archer only gets one attack in the front row. Put her in the middle and shoot fools full of holes.
Diana

The best possible source of back-row physical damage, and one of only two units in the entire game that gets three attacks in the back row! (two in the middle one in the front blah blah blah) A back row full of these things is HELL on enemy mages, but as back-row units themselves they're on the squishy side. Myself I prefer to use magic for the most part, but these ladies are certainly quite worthwhile in themselves.
Siren

The advanced female spellcaster, Sirens get tier-2 magic in the back row. Like an Archmage only much more exploitationy. Yeah I don't really know what kind of aesthetic they were going for here. She's like... a punk lounge singer?
Priest

Depending on who you ask, the Priest is possibly the most important unit in the game. They're upgraded Clerics; they heal more damage and they heal multiple characters in a small area. My opinion on them is mostly the same as my opinion on Clerics: build a couple of units around them to specialize in attrition, but bear in mind that every Priest in a unit is one less character to deal damage.
Dragon Master

For some reason the Dragon Master was made the best female frontliner in the game, with STR, VIT, and HP gains equal to those of a Paladin. The only real problem with them is only getting access to mediocre armor/not great weapons, and only getting two attacks in every row. Oh, they still boost Dragons too, which will become increasingly relevant as the game progresses. They have upgraded from wearing a dragon skull to wearing tiny dragon wings of some sort. Sure, doesn't look any sillier than Valkyrie headbands.
Freya

The upgraded Valkyrie, the Freya continues their role of ideally being suitable for either front or back row. As always, though, adaptability comes at the price of specialization. Dragon Masters are better in the front; Sorceresses are better in the back. On the plus side, though, where Paladins and Black Knights get first-tier magic in the back row, Freyas get second-tier magic (since Valks already had first-tier). Which is kind of cool.

Undead
Shockingly, the Undead and Demons in OB64 are completely unaffiliated and could not be more dissimilar in terms of game mechanics either. Where Demons are all about power power power (also Goblins sometimes), Undead are more gimmicky. They're pretty light on attack power for the most part, but their thing is that if they're dead at the end of a combat, they will revive themselves at full health. There are two ways to kill an Undead character for good: (1) kill them with a Holy-element attack or (2) wipe out their unit, which technically just makes them retreat I guess but they can't come back from that anyway.
If you'll recall me saying this earlier, dead characters are only permadead when they turn Undead. The only way to completely and irrevocably lose a Character, therefore, is to have it get killed with a Holy attack while undead.
Zombie

This right here is why you want to be conscientious about resurrecting all your dead human characters. If someone is still dead when you finish a mission, and that character has a poor Luck rating, there is a chance he or she will turn into a Zombie for no particular reason. Non-human characters have no danger of this happening to them, and I don't think it happens to anyone with a unique sprite either, although I could be wrong on that. You don't want this because Zombies are pretty horrible, and no other undead class is very good. If one of your characters gets Zombified, your two best options are (a) load an old save or (b) arrange to have them set on fire as soon as possible, because then they will turn into a Skeleton, which makes them (slightly) less useless. Two Bite attacks in the front, one everywhere else.
Skeleton

The fact that this guy is the offensive powerhouse of the Undead says a lot about Undead. Stat growth isn't great, but he/she is unique among the undead in that you can switch out her/his equipment. Basically like a slightly worse Berserker with post-battle regen but no chance of ever switching to a better class. Two attacks in front, one everywhere else. Created when a Zombie is hit with a Fire-element attack. Yeah. Just picture THAT. You're welcome.
Ghost

The final link in the Undead evolutionary chain, the Ghost is... basically a Witch. Its Nightmare attack deals no damage and puts the target to sleep. Y'know, I think Ghosts are actually BETTER than Witches. Hear me out -- you don't need to worry about damage output so stats hardly matter, and they are very unlikely to die as long as you're careful. I still won't be using any, but they're a viable status-causing class for that reason. Two Nightmares in the back, one everywhere else. Created when a Skeleton is hit with a Wind-element attack for some reason.
Vampire

Vampires have an interesting gimmick: their attack deals moderate Bane damage and then heals them for the same amount. This is kind of a cool idea, but there are a few problems with them. One is that once you go Vampire, you never go back. You're stuck with your curse for all eternity; go be angsty and creep on some teenaged girls 'cause you're gonna be stuck that way for a while (and everyone will call it romantic for some reason anyway). Another is that Vampires are the only undead who don't do the whole coming-back-to-life-every-battle thing. Lastly, during the day, they're stuck inside their coffins and can't move. While this is going on, your Vampire will not make any attacks, but its Defense will go through the roof because the coffin is made out of some kind of undead superwood or something. More interestingly than that, though, the Unit's terrain type will change to IMM. Which means that you can't go ordering it around, but it also won't move ever unless it gets wiped out, which is highly unlikely with that vampire in coffin-armor. This makes Vampires pretty useful as HQ guards... about half the time. At night they're no better at that task than anyone else would be.
Angel Knight

Sort of the inverse of a zombie. If someone's dead at the end of a mission and they are (a) female and (b) very lucky (in terms of both random chance and the hidden Luck stat), they could very well turn into an Angel Knight. If you have all the necessary equipment. More on that later. It should be noted that they aren't actually better than Ravens/Vultans in terms of stat growth, but they're good as sources of Virtue damage. And a huge pain in the ass to get yourself. More on that later.

Enemy classes
With exactly one exception, these are the classes I'll be able to fight but never be able to create for myself.
Grappler

Apparently the only possible vocations for a Bolmaukan as far as this game is concerned are "miner" and "Grappler." If it's a Bolmaukan and we're fighting it, it's a Grappler. Grapplers look and act a lot like Ninjas and are pretty much glass cannons. Can deal some pretty good damage but can't really take a hit. Be careful not to crit them into the back row -- from there they get Fatal Dance, which is basically a really big physical hit.
Knight Templar

Would you believe this is the best CG render of these guys I could find? They're not popular, apparently, as they are not story-important characters and we'll never be able to make one ourselves. Well, picture slightly more defense-oriented Paladins. They get three attacks in the front, but don't have quite as much offensive capability (and also carry Baldr Swords by default rather than Blessed Swords, which hurts them). They're very excited to talk to you about our Lord and Savior, Jesus Christ.

(OTHER CLASS DESCRIPTIONS TO COME AS I ENCOUNTER THEM)