Oscar

Oscar ("deer-lover," continuing his father Oisín's deer-associated name) grows up to become one of the Fianna's most feared fighters, known for a battle-fury that echoes his grandfather Fionn's own youthful exploits. He is a constant presence at Fionn's side through the Fianna's later campaigns, bound as much by personal loyalty as by blood.

His death at the Battle of Gabhra, fighting on opposite sides from his own kin in a war between the Fianna and the High King, is remembered as the blow that breaks Fionn's spirit and marks the beginning of the Fianna's decline — grief for Oscar is one of the recurring themes Oisín returns to centuries later when recounting the Fianna's story to St. Patrick.