What "final boss," or "final battle," do you hate the most?

[A Random Reader]

Dullahan from golden sun, he just uses djini storm, then charon.

Spoiler: This is how the battle usually goes when you don't summon rush him.

Dullahan use element swap!
Isaac's sol blade lets out a howl, Meggedo!
Dullahan takes 783 damage!
Piers used Granite!
a shield surrounds your party!
Sheba used pure wish!
Jenna gains 413 hp!
Isaac gains 410 hp!
Piers gains 416 hp!
Sheba gains 409 hp!
Flash is set to jenna.
Dullahan uses djini storm!
all of Jenna's djini are drained.
all of Isaac's djini are drained.
all of Piers' djini are drained.
all of Sheba's djini are drained.
Dullahan uses formina sage!
Isaac takes 1036 damage!!!
Isaac is downed...
Dullahan used charon!
Jenna is downed...
Piers takes 745 damage!
Piers is downed...
Sheba is downed...
Felix's party joins the fray!

Et cetera.

 

[Hutchy_Bear]

Yu Yevon from Final Fantasy X. Summoning my worst Aeon and letting him use it to beat up on my slightly less rubbish Aeon before unleashing its Overdrive so he than takes control of a mostly dead creature with an empty gauge. Repeating this process over and over until he's left with Anima/Magus Sisters with 12hp was a bad start to the battle. And after that it only gets worse when you have to fight him and all it takes is a couple of Overdrives before it's over. Most anti-climactic final boss ever.

Agreed. Coupled with the fact that you CANT die as you are automatically revived. It's not a fight if there is no challenge, I count the final boss as Jecht - may not be that hard but you can still lose it.

 

[foodmaniac]

The last boss of Persona 3. 13 form boss that gets progressively harder. Lucky she becomes a complete joke once you get about level 80 (level 70-75 is the recommended level).

 

[dark-amon]

I hate Sephiroth from Kingdom Hearts 2, way to hard!

He ain't exactly a final boss, but I'll play along. Did you ever fight him in Kingdom Hearts? Way harder.

To my most hated Final Boss: I guess I have to go with Ultimecia from FF8 just because the battle drags out for 4 battles wich is more of the annoying and long. Rather than the challenging.
I think it would be the final boss in Demon's Souls, if I had gotten to him before I got tired of the game.