Cu Chulainn, also known as Lancer in the Fate/Grand Order series, is a legendary hero from Irish mythology, renowned for his combat prowess and unwavering loyalty. In the series, he is a Servant summoned by Masters to participate in battles. Cu Chulainn is characterized by his fierce determination and warrior spirit, often seen wielding his iconic spear, Gáe Bolg. His agility and battle tactics make him a formidable opponent. Despite his fierce nature, he carries a sense of honor and is dedicated to protecting his allies, showcasing a nuanced personality beyond his warrior façade.