Gray (Fate) Hentai: Próifíl Carachtar & Bailiúchán

Fate series character. One of the main characters in Lord El-Melloi II Case Files. In Fate/Grand Order, she is summonable as a Assassin-class Servant. She is an assistant of Lord El-Melloi II at the Mage's Association's Clock Tower. She first met Lord El-Melloi II when he arrived in her hometown. She became his apprentice, and was admitted to the Clock Tower of London. She has a striking resemblance to Saber, which Lord El-Melloi II believes is because she's a distant descendant of King Arthur. (Source: Danbooru Wiki)