Being X/Relationships

Tanya von Degurechaff
Due to her being Atheist, he reincarnated her as a girl and forced her to become his prophet carrying a relic with a blessing coming from him. His goal is to make her and humanity acknowledge and praise his name as their Creator.

He goes into objects and dead bodies to force her to accept him as her creator, only to turn to taunting her. And also for her to have a undying hatred for him, destroying anything he goes into to satisfy her hatred.

Unfortunately, Tanya only sees him as "a cheating bastard" for constantly strong-arming her against her will to carry out his will by manipulating everything. Tanya seeks to kill him in revenge.

As Tanya has maintained her resolves, she will likely get the last in the end; something akin to "even if it's true, i still refuse to believe".

Mary Sue
He is using her as an apostle a.k.a tool for his ambition to make humanity and Tanya accept him as their Creator.