Rider (Fate/Grand Order - Medb)

(メイヴ) was the queen of in the.

Background
Medb was the queen of Connacht, part of a long line of queens ruling the country. After Fergus Mac Roich left Ulster due to the having his two sons killed "out of lust for young women", he defected to Connacht out of hatred for the king. Due to Fergus influencing Medb and the curse upon Ulster causing all born there to become feeble when invaded, Medb started a war. Cú Chulainn, not born of Ulster, was the only one able to fight, so he spent his days slaughtering her soldiers until they proposed that the war be held with one on one duels. Due to that she was loosing five thousand men per day, Medb reluctantly agreed to the terms, only advancing her army during the duels at the cost of only a single soldier per day. Medb ignored the treaty and still advanced, but only in unnoticeably small amounts due to having taken a public vow.

Cú Chulainn fought through many hard battles against her, requiring even a group of untrained soldiers sacrifice themselves to save him as he became more exhausted. Medb eventually schemed to have Cú Chulainn fight his close friend, reluctantly serving his lord even if it meant fighting his closest friend. The end of the battle resulted in Ferdiad's death and Connacht's defeat, followed by further defeat as the warriors of Ulster chased after Medb's retreating army. Cú Chulainn eventually captured her, but he treated her as royalty and returned her to Connacht without killing or shaming her. Vowing vengeance against him, she later returned after gathering many warriors with grudges against Cú Chulainn, cornering through the use of various means. He was forced to fight her army by himself, and he died after being entrapped by various plots of Medb.

Personality
Lancer describes her as a "warmongering lady" who hated having to back down.

Fate/hollow ataraxia
Medb is mentioned in Lancer's flashback.