[Julford Hajime]

Your reward for beating him besides rediculous exp and gold (The end bosses give 50000 of each, and I think Gades does here as well) is a sword that breaks the fuck out of the game.

It's slightly, slightly outclassed by endgame equipment, iirc, but I know it has an IP attack that hits an enemy 8 times. Basically, it's a one-hit kill on nearly every boss (I think only the optional bosses can survive) for the rest of the game, if a basic attack alone from the weapon-stronger-than-what-you-should-have-for-90%-of-the-game won't kill them.

And for realz, it's not worth the grinding. I've beaten that boss twice, once on a 4x Exp runthrough, and another on a glitch runthrough (There's a level 0 glitch that I used to give Tia rediculous stats and 999 HP. Makes the fight possible without grinding, but breaks the bejeezus out of the game. Enjoy ten minute loading screens at save points!). On the 4x run, I think I was hovering somewhere around mid-30s just to survive the fight.

When Lufia 2 wants to throw a broken-ass boss at you, it knows what it's doing.

EDIT: At that point, I beleive Jet Helm is the only stat reducer you have for enemies.

SOMETHING YOU MAY NOT KNOW ABOUT STAT UP/DOWN SPELLS: I watched through Chapter 3 so far, and you were confused about how Sluggish worked. Any time a spell increases or decreases a stat, it's by a set percentage (Either 50% or 25%, I can't remember which). Every time that spell is used on that target again, it cuts the gain by half (So a 50% boost/drop the first time would become a 25% boost/drop the second time, 12.5% the third, and so on).