Castle Fantasia

You are a knight named Varu who has a very beautiful girlfriend and is very happy with her. However, one day their kingdom get involved in a war, and the girl's parents die in it. After some time, an unknown religious organization appears in the city. Varu's girlfriend is in such a grief after the death of her parents, that she decides the world has nothing to offer to her, joins the adepts of the new religion, and leaves the city. Varu becomes very depressed after this separation, but when he learns the religious group which took away his girlfriend became an evil cult that kidnaps girls and seeks resurrection of demons. But even more awful is the fact his ex-girlfriend is now the leader of this cult...

[From Mobygames]