im not sure myself, i havent got to that stage yet (im in neverland) but i use this walkthrough whenever i get stuck, im sure it can help you to. Here is the link for the hollow bastion section of the walkthrough, I :
http://www.ffinsider.net/kingdom-hearts/walk12.php
if u mean where, hollow bastion beat replica riku
You have to go to Space Paranoids from Hollow Bastion. It will be in the Central Computer Messa
nothing special happens, you have to defeat 1000 heartless in one of the missions in hollow bastion
Kairi is from the world of Hollow Bastion. Hollow Bastion was formally Radiant Garden, ruled by Ansem the Wise.
It wouldn't be on there.
Easiest way, use trinity limit
Beat the final sector in hollow bastion in which you are required to be level 80 and higher and beat data roxas without dying
unlock all three keyholes(go through all three stories)at hollow bastion
The Keyhole in Hollow Bastion is in the Grand Hall where you fight Riku/Ansem, or where you fight Riku the second time.
His dark side, Serophith... to me he's hard to beat I found him by going through the battle area again
With your gummi ship.
you don't have to beat sephiroth to fight ansem I didn't. I think you have to go to hollow bastion to fight ansem.