Fergus mac Róich
In the tale he becomes the lover of Deirdre, a woman of great beauty, who is also desired by the king of Ulster Conchobar mac Nessa - as a consequence the lovers with Naoise's two brothers go into exile in Scotland (Alba). Eventually, Conchobar seeks to get them to return, but a series of unfortunate events (including a "geas" placed on Fergus mac Róich their protector and escort, as well as Naoise and his brothers' repeated disregard for Deirdre's prophetic warnings) and the treachery of Conchobar brought on by his desire for Deirdre, leads to tragedy.