Rolep was, according to the Watcher's Journal, a cavern in D'ni. It was within this cavern that his sight was restored to him after being blinded years ago by a vision of the fire of The Maker. According to the Watcher, "the first thing [he] looked upon was the stairs of Rolep. And [he] climbed to the top and beheld the great tree of D'ni, and wept."
It is unknown where this great tree of D'ni is, though some have speculated that the Watcher was referring to the tree in the Great Tree Pub (aka The Watcher's Sanctuary), and it makes sense, but since Rolep is not, as far as we know, anywhere near the Great Tree Pub's location in the J'taeri District of Ae'Gura, it is somewhat puzzling. More information will be provided as it becomes available.