Shadow House
Yudrein and Yuder, but twist: Yudrein is already unified with a Yuder. There had once been two Yuders, freak twins in the traveling circus who never aged (always looked like a kid), and one of them found out a secret, nearly got killed, but unified with Yudrein who was getting hunted by the Shadow House because Yudrein also is a freak of nature (child of human and Shadow). The two unified as they were dying and trapped in an underground shelter they both stumbled across while on the run.
Years later, the traveling circus visited the island again. Yuder tried to look for his missing twin, came across Gakane and Kanna who invited him to sneak into the manor (the only place Yuder hadn't checked yet), and Yuder does...
And becomes Yudrein's Living Doll! Yudrein having recognized Yuder and took advantage of their similar looks to sneak into the manor.
Kishiar and Keilusa wherein Keilusa is the Shadow and Kishiar is the Living Doll. Yuder is placed on Kishiar's team for clean up and Kishiar adores the new addition. Also, finds Yuder crazy talented, which helps Kishiar, Keilusa, and Faria's plans to rebel against Shadow House.
Faria (Shadow) and Rosa (Living Doll)
Duke Diarca is Edward in this AU.
Dudureli mushroom is fed to Yuder once to make Yuder drink a lot of water and vomit all the brainwashing coffee out of his system.