The movie was based off of a comic. I believe it was an independent web comic.
It wasn’t fully animated, the characters were like cut-outs, like the animated version of Dante’s Inferno by Sandow Birk and Marcus Sanders.
I saw it on Hulu between 2011-2014.
The main plot is that aliens, thought to be demons, came to Earth, and enslaved humanity. People believe the biblical apocalypse has happened.
A teenage boy is wondering the wasteland trying to survive.
If I remember right, the movie starts with him living with a priest of some kind.
It was very grim, dark, and violent.
One scene that sticks out, the main character gets raped/beaten by a female alien/demon, that has a cyborg penis.
I hope this is enough info, it’s been almost 10 years since I watched it, and I’ve been looking for it for the last 3 years now.
Thank you for your time!
Godkiller: Walk Among Us (2010)?
https://www.imdb.com/title/tt1384961/