In one scene, several high school boys are in the locker room shower and they begin making sexual remark to a less popular student. It eventually leads to one of them forcibly kissing the boy who's being bullied.
There's a relationship between two high school students that is very abusive (hitting, pointing a gun, etc). We also see some domestic violence in the main character's household.
I would also mention that Lucifer and the angel's characters are all incarnated. They were all possessed from birth and are the embodiment of supernatural spirits in human form.
It was not entirely clear to me if what we see is a mental institution or a prison, but a character is committed due to killing someone else and ends up in confinement where he is abused by the guards.