Satan is the source of all evil in Christian theology and a pleasant and charming, though very very very very not-nice in the end, person, if the tales about him are true.
Obviously, they are not the same thing.
If your character is the "child of Satin", who is his mother? Fleece? Raglan? Wool? Flannel? Tulle? ...Oh. His mother is an angle.
How the hell does THAT work out, I wonder?
Oh, you mean Satan and an angel. If that's what you mean, please say so.