Kingdom Hearts Message Board  

but there are special bosses after you defeat hollow bastion in the old worlds like agrabah

Yeah at Agrabah there's Kurt Zisa.
And at Neverland there's the Phantom.

also, you could consider sephiroth and ice titan at the cooliseum hidden bosses.

I am sad I have beaten everyone except the phantom (including sephiroth) how can I beat him?

I don't know if i just was lucky, but i have no clue how that guy got to first seed. Stay close to his feet, but not too close, or you'll get stomped on. Pull lots of combos on him, but not special combos like Ragnorak and Ars Arcanum, that'll pull you under his feet and you'll get crushed like a bug. When he falls on his knees, then use the special combos. Attack quickly becuz eventually (i think) he has a harder mode. I never saw it.

Ok Ive got a question in the End of the world how do I beat the thing that looks like a volcano with wings?

Go behind his head and attack him with combos. After about 5 combos, fly away. Wait for him to do the inferno all around him like move, then rush back and do it over again. (You might need to edit the amount of times to do the combos, i haven't played in a while). It might take a little longer, but its a surefire way to win.

yeah it is basiclly like the battle with ursula except easier