Sieg

Homunculus (ホムンクルス) is part of the Black Faction in the Turifas Holy Grail War of Fate/Apocrypha.

Background
Gordes Musik Yggdmillennia created Homunculus by using the Einzbern alchemy technique. He was orginally designed to serve the Yggdmillennia by acting as a prana supply for one of their Servants along with a number of other homunculi.

His body turned out to be a defect with a fragile magic circuit and according to Archer of Black's diagnosis, he has no longer than three years to live.

Role
He suddenly woke up with an ego and befriended Rider of Black. With the chaos Berserker of Red has caused, he uses this opportunity to escape with the help of Rider of Black. He was mortally wounded by Gordes and his pursuers and was on the verge of death. Saber of Black transplanted his heart into the Homunculus body and successfully revived him.

He receives the heart of the true Siegfried and has the ability to shapeshift, taking the form of the Saber of Black when fighting against the Saber of Red. He loses and is about to be beheaded by the Saber of Red.