I guess that would be Heaven, it's the one on the East side of the world.
Besides, I think Hell is mostly dragons of sorts, and Heaven is Ochu's, Malboros, and Tri-Faces

BTW: There's no way to get to Islands of Heaven and Hell with the Garden, is there? I'm pretty sure you have to have the Ragonoak, but if anyone knows how to go earlier, let me know!