Cu Chulainn Alter
Cú Chulainn (Alter) is a Berserker-class Servant in Fate/Grand Order and related titles within the Fate franchise. He is a transformed version of the Ulster hero Cú Chulainn, brought into being by Queen Medb's wish upon the Holy Grail for a wicked monarch to stand at her side. Serving as the chief antagonist in the North American Myth War chapter (E Pluribus Unum), he acts as an unstoppable Mad King who ravages the American continent, embodying pure destruction and battlefield desolation.
Overview
Cú Chulainn (Alter) is a Berserker-class Servant in Fate/Grand Order and related titles within the Fate franchise. He is a transformed version of the Ulster hero Cú Chulainn, brought into being by Queen Medb's wish upon the Holy Grail for a wicked monarch to stand at her side. Serving as the chief antagonist in the North American Myth War chapter (E Pluribus Unum), he acts as an unstoppable Mad King who ravages the American continent, embodying pure destruction and battlefield desolation.
Appearance
This altered form features long blue hair tied in a ponytail, striking red eyes, sharp teeth, and facial markings. Although ambient lighting in certain artwork gives him a darkened complexion, his skin is actually slightly paler than his original form. He wears earrings, gloves, and a hooded outfit over his muscular body, which is covered in black and red magical tattoos. Sinister beast-like bone armor encases his arms and lower body, accompanied by a massive tail. His signature spear, Gáe Bolg, is corrupted into a crimson-and-black weapon bristling with sharp thorns.
Personality
Devoid of his living self's boisterous and noble nature, Cú Chulainn Alter acts like an emotionless combat machine dedicated solely to battlefield slaughter. Derived from Medb's distorted obsession, he functions as an overwhelming tyrant focused entirely on subjugation. Despite his high Mad Enhancement, he retains enough reason to converse. When contracted to a Master, he strictly adheres to his function as a Servant, obeying orders with cold professionalism and risking himself in battle out of rigid adherence to his role rather than personal affection.
Abilities
Classed as a Berserker with Chaos, Evil, and Earth alignments, he possesses extreme physical strength and agility. He automatically channels Rune Magic for Magic Resistance, using it further for physical enhancement and cell regeneration. His skills include Roar of the Spirit to reduce enemy stats, Protection from Arrows for non-magical projectile evasion, and Battle Continuation to survive critical wounds. His Noble Phantasm, Gáe Bolg, is a full-power throw causing wide-area destruction and instant death while runes mend his damaged body. His second Noble Phantasm, Curruid Coinchenn, equips a sea beast's exoskeleton as bone armor, granting EX-rank Strength and sprouting internal spear tips inside pierced foes.
Background
This incarnation was created through Queen Medb's wish upon the Holy Grail for a malevolent king to reign alongside her. Rather than taking the monstrous berserker form described in Irish mythology, he materialized in a state influenced by the sea beast Curruid. Backed by unlimited magical power from the Grail during the North American Singularity, he fought as a catastrophic force capable of defeating even his former master, Scáthach. Following the singularity's resolution, he became available for summoning as a Servant to aid Chaldea.
Relationships
Queen Medb, the architect of his creation, expresses intense affection toward him, though he responds with complete detachment while fulfilling his role as a king. He views his former mentor, Scáthach, as an obstacle to overcome, engaging her in a fierce duel during the singularity. Toward his Master, Fujimaru Ritsuka, he remains emotionally distant yet strictly obedient. He also interacts with various other Servants across different encounters, including Emiya Alter, Ishtar, Arjuna Alter, and Rama.
Trivia
Fans frequently address him by nicknames such as Cu Alter or Mad King. Despite his large tail and heavy bone armor, his official weight setting is only two kilograms heavier than his standard Lancer self. While dynamic backlighting in his primary card art leads to the misconception that he has dark skin, official visual sheets confirm his skin tone is actually slightly paler than usual. Though generally portrayed in serious story roles, he occasionally appears in comedic spin-offs like Fate/Grand Carnival, where he gets humorously dismissed simply for being one of too many Cú Chulainn variants.
