Berserker (Fate/Grand Order - Phantom)

Berserker of Shinjuku (新宿のバーサーカー) is a Berserker-class Master-less Stray Servant appearing in the Grand Orders of Fate/Grand Order. He creates various Coloratura puppets, including imbuing the Phantom of Christine Daaé into one.

Identity
Assassin's True Name is the Funtom obu ji Opera. A masked killer. The mysterious person who appeared in “”, a novel set in the 19th Century――perhaps, the person who became its model. Settling down and inhabiting in an aqueduct that is like a vast underground labyrinth beneath the opera house, he was charmed by a young and chaste actress who was viewed as purity itself, even guiding her into becoming a diva, and conducted serial murders on behalf of his unfulfilled love.

Shinjuku: Malignant Quarantined Demonic Realm
The Phantom, as a Berserker, appears in the "Shinjuku" Singularity, accompanied by a Phantom, Christine, that he placed into a doll. 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, puppet-like enemies.

The Phantom and Christine appear for the first time when they ambush Ritsuka Fujimaru and Moriarty, wanting to kill them both. Ritsuka and Moriarty manage to stall them long enough to escape with Moriarty distracting them by blowing up a gas station. The party later attempt to take out the Phantom by using a reprogrammed Coloraturas to create a large explosion. This gives Moriarty and Ritsuka enough time for them to fight the Phantom while Artoria Alter and Jeanne Alter hold back the other Coloraturas. After they defeat Christine, EMIYA Alter appears, finishing off the Phantom.

Abilities
During the Shinjuku Phantom Incident, Eric displayed a remarkable aptitude for engineering and puppet-craft. He maintained an army of around three hundred Coloraturas automatons, two hundred of which were programmed to always stand guard around Phantom's base, the Shinjuku Opera House, while the remaining one hundred would patrol around Shinjuku, kidnapping anyone they come across. This was how Eric would replenish his army. Those who were captured by the puppets would be brought back to the opera house alive, allowing Phantom to extract and lobotomize their still living nervous system to then transfer it over to a puppet body, creating completely loyal, and mindless slaves. Should any of the Coloraturas get destroyed, they are then immediately replaced by the puppets in reserve to maintain their numbers. All of this effort however, ultimately served another purpose. Having hijacked the Shinjuku P/A system, the Coloraturas are slaved to Christine and her performances that broadcasted over the P/A system. They are her eternal audience, programmed to admire her performances and periodically give standing ovation to her.