Board Thread:Questions and Answers/@comment-31479589-20190528023204/@comment-31479589-20190609152200

June just said to Deng Rao in Ch 4 that Emperor will return soon, meaning he is probably in the process of recovering. He never really crucial to the story anyway, his only purpose is to be the last boss of Ch 3, a very tough one at that. They just mention him as the Sphere Keeper and after said Sphere is broken, his role is no longer relevant.