Fergus Mac Roich

Overview

A Saber-class Servant in Fate/Grand Order, hailing from the Ulster Cycle of Celtic mythology. Formerly a king of Ulster and a prominent member of the Red Branch Knights, he is widely recognized as the foster father and sword instructor of the great hero Cú Chulainn. Characterized by his large-hearted personality and insatiable passion for alcohol, combat, and romance, he abandoned his royal position to live as a true warrior. He serves as an open-minded and dependable figure who wields a legendary spiral sword.

Appearance

He is a heavily muscular warrior characterized by blue hair, narrowed eyes, and scars across his body. In battle, he carries the massive magic sword Caladbolg, which features a drill-like rotating structure used to crush the ground. In certain summonings, he can also manifest in his boyhood form as a youth.

Personality

He possesses a boisterous, generous, and fearless temperament completely devoid of jealousy. An avid drinker and big eater, he is notoriously upfront about his romantic interests, often demonstrating Celtic squats to show off his physique to attractive women. Despite his shameless flirting, he is fundamentally gentlemanly, never forcing himself on anyone and prioritizing mutual consent. Towards companions and younger individuals, he acts as a dependable, protective older brother who makes clear-headed decisions in crucial moments.

Abilities

He possesses exceptionally high physical parameters alongside the Magic Resistance and Riding skills. His personal capabilities include Bravery, Mind's Eye (True)—derived from his insight in discerning divine traps—and Nature of Rebellion. His primary Noble Phantasm, Caladbolg, is an Anti-Army weapon capable of indiscriminate terrain destruction; famous for shearing three hills in legend, it releases a rainbow-like blade of light that served as the prototype for later holy and magic swords. When unleashed at maximum output as Ki-Caladbolg, it plunges into the earth to shatter total landmasses on an island scale.

Background

Born a prince of Ulster, he once yielded his throne to his half-brother Conchobar for a year, ultimately realizing he lacked the disposition of a ruler. After King Conchobar committed acts of treachery, he left the Red Branch Knights in fury and joined forces with his lover, Queen Medb of Connacht, during the great war against Ulster. Bound by a geis with his former pupil Cú Chulainn, he deliberately feigned retreat in combat, which caused Medb to distrust him and exclude him from subsequent campaigns. He was eventually assassinated due to the jealousy of Medb's husband, King Ailill. In Fate/Grand Order, he appears in the North American Singularity and the subterranean world of Agartha.

Relationships

He shares a deep bond with Cú Chulainn, acting as his uncle, sword instructor, foster father, and comrade-in-arms. He was previously the lover and ally of Queen Medb, though he views her personality critically despite recognizing her romantic aspects. He holds the warrior Scáthach in high esteem as a master while casually attempting to court her. Toward his Master, Fujimaru Ritsuka, he acts as a protective mentor figure while remaining open to romantic advances regardless of gender. Additionally, he formed a connection with Scheherazade, helping alleviate her mistrust of men.

Trivia

His wish upon the Holy Grail is to once again be intimate with both Queen Medb and his wife, who is a forest goddess. A memorable moment in Fate/Grand Order involves his Valentine's return gift, where he hilariously misinterprets the Master's gesture as a romantic invitation and immediately reserves a private room. Additionally, his legendary sword Caladbolg is identified as the mythic prototype for numerous famous blades throughout history, and its design has even been adapted by other Servants as a projectile weapon.