Part 87: Death Is Not A Hunter Unbeknownst To Its Pray
Maya's Theme
So, let's really talk about the Reaper for a second here. We did this a bit way, way, waaaaay back when we first entered Tartarus for real, but this is a little more focused than "he will kill you." See, we CAN take him at this point.
It's not the most elegant solution, but after I spent a couple hours grinding, Odin hit level 65 and learned one of the best passive skills in the game. Spell Master is an insanely good skill that halves the SP cost of spells that Makoto casts with that Persona. Notably this includes Fusion Spells (keep that nugget tucked away in the back of your mind for later). He also learns Thunder Reign at level 63 which is unique to him, outside of fusion inheritance. I hope you remember what that does.
Elec Amp is nice, but not required for this. Nothing else here is, for that matter. The Charges are actually even outright detrimental if we use them. Some kind of Wind resistance wouldn't go amiss, just in case, though.
Mass Destruction (Reincarnation) 
So, if you're playing on Normal or Easy you have an inherently much easier time. You won't get your own advantage, but Hard Mode gives enemies that are even remotely aware of you advantage. It's a really bad decision, especially when you smack 'em in the face and they get the first turn regardless.
This presents a bit of a problem right out the bat. See, The Reaper is a bit of a rarity in that he's level 99. He has 5000 HP (up from 4444 in Vanilla), 12000 SP (up from 9999 in Vanilla), and stats designed to just murder you.
66 Strength, Endurance and Luck are his lower ones. His Magic and Agility are 99. Just to make things a bit worse, since he counts as a boss, his Expel and Curse resists are Null of course. Slash, Strike, Pierce, Fire, Ice, Elec and Wind are all resisted. Every last one. Yay.
Since the Reaper gets to do things, let's see what he CAN do. Naturally, he has all four single target Dynes.
He's fairly aware of our elemental resistances too, so he doesn't whiff with these. If he's busting one out, he's aiming explicitly at a weakness just for good measure.
He can also sometimes just not care and bust out any of the four Ma-dynes, just to hurt everyone. This isn't actually as bad as it sounds, since the MT spells have slightly lower power and accuracy than the ST equivalents (which is why your party members don't like using them all that much sometimes).
...It's still pretty fuckin' bad though.
In an ideal world, he'll use his first move to focus on removing a resistance instead. This is not guaranteed, of course, so if he doesn't do that and instead opts to just murder someone (he quite liked to kill Junpei... or Makoto... on my end), you could just run away, heal up and try again.
Except on Hard when you basically need Trafuri in some way to succeed at escaping. Welp!
He also has both flavours of instant death. Just Hamaon/Mudoon, thankfully. The Reaper does not have Samsara or Die For Me! which sounds like an odd mercy, but they're special, unique spells so only Makoto will ever get them.
Now, like I said before, he's only fairly aware of our elemental resistances. That does not extend to Expel and Curse, which he will gladly throw at anyone.
Since he has 99 Magic, he does quite like his spells but he has some physical skills he can bust out every now and then too. Myriad Arrows is a multi-target skill that hits 1d2 times. It has a base power of 140, has an 87% accuracy and a 3% crit rate. It's thoroughly okay, and yet it remains the second strongest multi-target Pierce skill because there's only 3.
This isn't even an exhaustive list of what he can do by the way. There's some other spells he has but he doesn't like using them super often.
So, uh, remember how he likes casting spells? And isn't immune to anything that isn't instant death? Let's take advantage of that. This game's pretty nice about letting you do that, after all.
.....Except here. The Reaper is the first of a few dudes who look at that mirror and tell you to fuck off. Megidolaon is the third weakest Almighty spell with 600 base power (...yes, really) but remember how the Reaper is level 99? And has 99 Magic?
Yeah, it still fucking ends us right now. Not doin' that then!
...At least not right now. Later on the level scaling on damage makes it very survivable.
But, here's a fun quirk of doing the fight early. The turn order is the second enemy to contend with. If you watch the FES boss videos, you've probably noticed I check it at the start of almost all of them. It's not super critical for the most part (it just lets me know what to expect, really) but here it matters. If the Reaper's second, like he is here, then welp. Time to try again.
Next on Makoto is super-misleading, by the way. That just means its currently his turn. Yeah, it's not the clearest thing.
In an ideal world, he'll be 5th, but 4th is... fine. It's not great, but it's workable.
Just gonna set everyone to Knock Down. I'm including Junpei here, because the AI is really bad in this kinda scenario. It'll see that the Laevateinn has the highest base power out of all his options, and that every element is resisted, and so opt to use basic attacks. Blade of Fury, if it hits, will outdamage the Laevateinn by a not-insignificant amount considering the damage we do is pretty small.
Also, the Elemental Attack weapons like the Laevateinn, Gae Bolg, Mjolnir etc. cannot crit. Don't think I mentioned that before. It's another odd little quirk that normally doesn't matter, but it's exactly why you don't want to use them here. Makoto can have one equipped, if you want, but if you're being smart and optimal, no one else will.
So, we want to use Thunder Reign on Makoto's turns. We want to use nothing else, ever. The damage isn't great, but the 100% Shock is what makes it a really good skill in general, of course.
Thunder Call isn't as viable, because it costs more at this point (over 40SP a pop) and the damage is a little less than Reign.
Since Spell Master makes Thunder Reign cost 16 SP a turn, we can actually theoretically win. Without it, its cost of 32 is... very untenable. We don't really have the chance to use a Precious Egg or any other SP restoring item mid-battle without that being a giant roll of the dice. He MIGHT cast an elemental Break, or he might just instantly kill
Shock is what we want for this fight over any other ailment because it can be inflicted, and it gurantees crits. Fear would be super ideal, but well... of course that doesn't work here. This isn't Persona 5; ain't no getting an insta-kill on any Reapers here.
Checking the turn order lets us know that it goes Ken > Koromaru > Reaper, so after Ken knocks the Reaper on his ass, we CAN pull out an AOA.
...But the Reaper is level 99. Even though 66 Endurance is not that much compared to our general Strength and the power of our equipped weapons, the level disparity scales the damage down. Remember, this is Almighty elemental so he does not resist it and yet it still does damage on par with (Tarukaja/Boost/Amp) Thunder Reign. But, hey, its sorta technically free so still definitely take it.
Not for Koromaru, though. He can use his One More to just wait. Purely because the Reaper is next.
That forces the Reaper to use his turn to remove Knock Down. It's nice that he's not immune to that, for that matter. It wouldn't be that out there (and we've even seen it before; Arcana Strength was immune to it).
Just, uh, just hope that Thunder Reign doesn't miss. It might not be a big deal.
Or it might just be an instant game over, depending on entirely what the Reaper wants to do.
But, yeah, that's how you kill the Reaper early. It is slow, boring and emphatically not worth it. There's no reason to do it at this point other than to prove you can exploit a simple loop of knocking him on ass and making him waste his turn getting up. There's no special bonus prize for proving that you can grind past the point of it being fun.
Which is why I seem to keep on doing it. Fortunately(?), this isn't canon so Odin does not have these fun toys yet back in the real world.
There's other, less tedious, ways to fight this guy but we're nowhere near pulling them off right now. This isn't the last time we're gonna see our good ol' pal, Death The Reaper. Next time it'll be for real, don't worry!