Cú Chulainn is a prominent Servant in the Fate/hollow ataraxia visual novel, based on the legendary hero from Irish mythology. He is summoned as the Lancer-class servant, renowned for his exceptional speed, agility, and mastery of the spear, Gáe Bolg. Cú Chulainn is known for his brash personality and strong sense of honor, often displaying a cheeky and straightforward attitude. In the series, he plays a vital role as a formidable combatant and interacts with various other servants and masters.