Archer of Black (Chiron The Centaur)

Archer of "Black" ("黒"のアーチャー, "Kuro" no Āchā?) is the Archer-class Servant of Fiore Forvedge Yggdmillennia as part of the Black Faction in the Great Holy Grail War of Fate/Apocrypha. He was not part of the designs for the original canceled online game project.
Archer is Chiron (ケイローン, Keirōn?), a centaur, half man and half horse, who was known as a great sage among his kind. He mentored numerous famous heroes starting with Heracles, Jason, Asclepius, and later also mentoring Achilles, in Greek mythology, and he became the model for Sagittarius, the Archer in the sky. He is the son of the Titan Cronus, patron of the harvest and the earth, and the deity Philyra, making him a Divine Spirit that would not normally qualify for the status of Heroic Spirit.

He was eventually hit an arrow treated with Hydra poison, and due to the extreme agony it caused him, he gave up his immortality to be released from it. He lost his complete Divinity along with his immortality, allowing him to become an existence that could be summoned by the Grail.