Rogash is a fictional troll chieftan of the North and only appears in the computer game, The Lord of the Rings: The Rise of the Witch-king. This is not unbelievable, it's just that Tolkien never mentioned a Rogash. In the Rise of the Witch-king, Rogash is won over by the Witch-king and he and his trolls help the Witch-king to destroy Arnor.