Part 60: Prism explains the Lemina Bug in more detail (Part 2)
What Happened?You broke pointers.
Characters who aren't in the party aren't stored in memory in the same place as ones that are currently in the party. When you scroll up to Lemina's Mystic, you're not actually powering up Mystic - you're messing with whatever comes after her. I don't pretend to understand the exact mechanism by which Eternal Blue runs its pointers, but it seems that Hiro's magic and inventory is what gets some data written to it that shouldn't be, letting you rummage around in an area the game isn't normally prepared to let you touch in that manner.
Obviously, this doesn't happen in the Japanese version because the Magic Power Up menu always defaults to Hiro, so you can't ever scroll starting from a character that isn't in the party and get to Lemina's Mystic magic to break it.
So What's In There Anyway?
Mostly junk.
The majority of the items are just the usual stuff you get during the game. There are eight items that are complete but unused, and a bunch of ones that are just random data that the game tries to read as items. Some of these are interesting - there's a weapon that is equippable by anyone and has +0 attack power but +96 attack swings - but I'm not going to go over them because they're not items that were left in the game by mistake. They're just random data being read as if it was an item.
But here are the eight dummied-out items that are actually complete in every way. They've got names, icons, coding, everything.
BATTLE SHADOW - Attack +80, # of Attacks +1
The Battle Shadow is a weapon used by Hiro. It's nothing incredibly special, though the +1 swings is nice because most swords don't have that. It's between the Iron Scimitar (67) and the Flame Saber (86) in power, but the +1 swings boosts that quite a bit.
WIND SWORD - Attack +150, # of Attacks +1
The Battle Shadow except better. It would actually be a pretty solid choice until he got one of his final two swords.
GODDESS DRESS - Defense +45, Agility +20, Allows Counterattacks
This is equippable by Jean (both dancer and karateka). It's quite good, but there's a wrap for karetekas, the Immortal Wrap, that has a very similar power (42), Attack +8 instead of Agility +20, and maintains the counterattacks, so it may simply have been made redundant.
GODDESS FAN - +99 Attack, # of Attacks +1, Constant Bonus Damage, Confusion Attack
I already described this, but on checking it has 'constant bonus damage', which is practically 'hits twice per swing', thus making it much better than +99 looks. It's end-game material and very good even for that, especially given the fan's range.
GRIM RAPIER - +180 Attack, *Dragon Damage, Freeze Attack, +10 Agility, does lightning damage
This is a Leo-only sword. Dragon Damage makes it instant kill certain enemies sometimes in locations we haven't seen yet (I'll note them later). It's kind of glitchy; it makes the critical stars animation and then they vanish. It also does bonus damage to just about everything because it clearly wasn't good enough. This would be Leo's best weapon if it was allowed to exist.
GRIM SABER - +190 Attack, Kill Attack
Hiro's miniature version. Much worse than the Grim Rapier; the kill attack doesn't work that often (for those who have played the game before, it works the same as the Fury Bow) and no bonus damage. This wouldn't be endgame material for Hiro; he's got three swords better than it that are actually in the game.
PICK AXE - +150 Attack, Surefire Attack, Bonus vs Mines Enemies, # of Attacks +1
A weapon for Ronfar; it's classed as a club or flail. Counting the +1 Attacks this would probably be his best club for damage (he has a 170 and a 200, but they don't have the bonus swing, and Ronfar gets relatively few swings to begin with), aside from the fact that it has no magic-based side effects and he's probably better off with his choice of several other options. He really shouldn't be meleeing that much. The exception is in the mines. It's great in there.
And finally...
DARK SCIMITAR - +140 Attack, +10 Agility, *Kill Attack
Our treasure! Only Hiro can use this. The text claims it has a kill attack; it does not. The Dark Scimitar uses 26 MP every time it would not ordinarily critical to critically hit. There is no way to turn this off and Hiro can go through his entire MP pool in two rounds.
So basically, after all that, it wasn't worth it anyway.
All of these items exist in the Japanese game, too, except there's no Lemina Bug so you have to add them manually. They work just as well as their English counterparts, as far as I know (I know the Dark Scimitar does, but for some reason nobody bothers to test stuff like the Battle Shadow).