In Fate Grand Order, the Caster class, including Caster, is a Caster-class Servant, invoked by Ritsuka Fujimaru. This class showcases distinctive abilities like Item Construction and Territory Creation.

Medea, in the Subcategory Holy Grail War of Fate/Labyrinth, serves as a Caster class servant under the master Souichirou Kuzuki. She is depicted as Neutral Evil. Trained by Hecate, the goddess of witchcraft, Medea hails from Colchis in Greece, being the daughter of King Aeëtes.

Caster (キャスター, ?) is the Caster-class Servant of Souichirou Kuzuki in the Fifth Holy Grail War of Fate/stay night. She also acts as the Master of another Servant, Assassin Class Servant in the same war, too.

Caster, a Heroic Spirit of Spells and Sorcery, excels in magecraft and wields high-caliber sorceries. They possess an exceptional Territory Creation ability, reflecting their craftsmanship. They also have a unique skill to understand and confront …

Tamamo-no-MaeWP (玉藻の前WP?), Class Name Caster (キャスター, Kyasutā?), is the Caster-class Servant available to be chosen by Hakuno Kishinami in the Moon Cell Holy Grail War and is the former Servant of Twice H. Pieceman in Fate/EXTRA and Fate/EXTRA CCC.

Caster was summoned shortly before the Fourth Holy Grail War began. His Master was Ryuunosuke Uryuu, a serial killer who unwittingly performed a successful summoning ritual using the blood of a murdered family.

She is an honored guest of the Ryūdō family, permitted to live at their temple until the preparations for her marriage have been finalized. A gorgeous and talented yet mysterious woman of high stature, her presence has attracted the attention of trainee priests and even Issei.

Caster is a heretic who has made a personal enemy out of Tohsaka due to her draining the townsfolk of mana and nearly killing them in the process. She is ruthless, talented and determined. Assassin guards the gate of her base of operations and is her Servant.

Caster is a character from the Fate / Stay Night visual novel / anime. A mysterious woman of high stature.

The point of this post will be to see what servants actually fit the requirements of Caster, according to their legends - Fate or real versions. Some are more ambiguous than others, and some will be cases of interpretations.