Bruno, initially identified as the Mysterious Man, is a secondary antagonist in Fire Emblem Heroes. He is an enigmatic man who occasionally appears before the Order of Heroes.
He is a prince of Embla, he and his mother were despised by the royal family. Eventually claiming she shared imperial secrets with Askr, they imprisoned her, causing her to die in isolation, while he himself was banished to the border despite only being a child.
In his first appearance in Chapter 9, he faces the Order of Heroes at first, but eventually aids them, as he warns about Veronica's attack on their summoning grounds. Later, he claims to have knowledge about Zacharias, but refuses to say anything more before disappearing.
In reality, he IS Zacharias, which was an alias used by Bruno to get closer to the Askran royal family.