Phantom of the Opera

Phantom of the Opera is an Assassin-class Servant.

Epic of Remnant I: Shinjuku
The Phantom manifests as a Berserker in the Shinjuku Singularity, accompanied by Christine Daaé, a Phantom he placed inside a Coloratura, a doll made from humans. He is part of the Phantom Demon Alliance along with James Moriarty, EMIYA Alter, Yan Qing and Hessian Lobo. He resides in Kabukicho, commanding hundreds of Coloraturas.

(Source: TYPE-MOON Wiki)