playing valkyrie profile i was in the final stage and i went into some room with a huge fucking green dragon called bloodbane with a savepoint before him. i saved >.> then when i engaged the music was different and i took a crap. was way more challenging than the final boss and i complied a killer strategy and kicked his ass in like 4 tries lol there's an extra stage with a room that has TWO bloodbanes.. scary.
not the last... but the hardest in the game
trying to kill the damn thing took me at leat 30min...
the firt time of course... next try well... Selphi rules
For Fighters I'd say I-No from Guilty Gear XX
For RPGs I'd say... Lucifer in Shin Megami Tensei Nocturne, but every boss was awesome there.
For Plataformers I'd say Marx Soul from Kirby Super Star Ultra
and the list goes on...
For adventure, for me (when I was younger) Bowser on Super Mario 64 was the hardest boss I ever fought (sad I know)...
For RPGs I'd say... Lucifer in Shin Megami Tensei Nocturne and Elizabeth from Persona 3 still send chills down my spine.