Rated M for mature. There are a few Violent moments and yes they get mature. There's a lot of shooting zombies and one part cannibal corpses were shown. And an occasional use of the F word in the language department.
Enochian is used by all angels. Angel memory and directives are hardwired into their brain through Enochian, as evidenced by Naomi's work with Samandriel. However, it also has been used by a few other creatures as well.