Fazendo parte de Radiant Garden, Hollow Bastion (Fortaleza Vazia, em tradução livre) é uma das principais localizações da serie Kingdom Hearts. Hollow Bastion é considerada a parte central de Radiant Garden, constituída pelo castelo e as moradias ao redor dele. No início de Kingdom Hearts II, é tido como Hollow Bastion esse mundo inteiro, porque ainda não está completo.
A principio em Hollow Bastion morava Ansem o Sábio e seus seis aprendizes, com o tempo Ansem foi explorando cada vez mais sobre a escuridão dentro do coração dos seres, mas com o tempo ele foi vendo o perigo e cessou as experiências; mas seus seis aprendizes foram corrompidos pelas trevas e baniram seu tutor para o Realm of Nothingness. Em uma inderteminada época, Malévola tomou conta de Hollow Bastion.
As a researcher and ruler of his world, he studied the Heartless and delved into the many secrets of the worlds. While studying the heart and the darkness within it, he was possessed by darkness and ultimately destroyed his own world. He sacrificed his body to attain great power, and later possessed Riku's to regain a physical presence. Failure to stop him means the end of all worlds.
A sorceress of frightening power. In the last adventure, she controlled the Heartless and led a group that was trying to harness the power of darkness. As part of her villainous plan, Maleficent tricked Riku into making the choice to dive into the realm of darkness.
In the end, Maleficent yielded to the power of darkness herself and was defeated by Sora and his friends. But by using her last bit of evil power, she was able to come back again some time later.
A tough and mean former steamboat captain. Donald and Goofy know Pete real well - he's so bad that King Mickey was forced to banish him to another dimension.
Maleficent found Pete there and helped him escape from exile. Since then, he's been traveling the worlds, assembling an army of Heartless for Maleficent. It's pretty certain that the two of them are planning to take over and rule all the worlds.
A troublemaker who once lived in the same world as King Mickey, Donald, and friends. But after mouthing off and getting temporarily banished, Pete was approached by Maleficent and became her loyal servant.
The datascape isn't the first place he has meddled with, but now that he's wandered in, he is hoping this will be his ticket to ruling a world or two.