Common Sense Note
Parents need to know that Legion is extremely violent and follows a negative, apocalyptic plotline in which God has given up on mankind and sends an army of avenging angels to wipe out most humans. There's no end of blood, dead bodies, and strong language (including "s--t" and "f--k"), which makes it iffy for everyone except adults and older teens. Ultimately the movie celebrates empathy and selflessness as the saving graces of the human race, but these things come packaged with a large quantity of brutality.
Sexual
Content
Not really an issue, except for the teenage character Audrey, who wears a skimpy, revealing outfit throughout the movie. There's also a brief discussion about abortion.
Violence
Heavy fantasy violence throughout, including fighting, guns and knives, bullet wounds, slices and dices, car crashes, and many dead bodies (including the bodies of possessed, zombie-like creatures). In one scene, an angel slices off his own wings and stitches up the bloody wounds. A possessed old lady bites a man's neck; she's hit in the head with a frying pan and eventually shot. A swarm of bugs attacks. Other disturbing imagery includes a man hanging on an upside-down cross with pulsing boils all over his body. He explodes and sends lethal acid flying. "Zombie" children are the victims of violence, and one zombie wields a knife and tries to attack a pregnant woman.
Language
Many uses of "f--k" and "s--t" in all their permutations, plus "c--t," "hell," "damn," "goddamn," "bitch," and "oh my God." Multiple uses of "God," both as exclamations and within discussion of the movie's themes.
Social
Behavior
The movie's overall plot/tone is negative, but it moves toward a kernel of optimism. The story is based on the idea that God has given up on mankind and has sent an army of avenging angels to possess the bodies of the weak and destroy everyone else. But the angel who was supposed to be in charge of the mission decided to disobey because of his enduring faith in humankind. He finds good and selfless things about some humans, especially their ability to give when others are in need.
Consumerism
Characters drink Busch beer in a handful of scenes, but it's never mentioned by name.
Drugs / Tobacco /
Alcohol
Bob drinks beer in several scenes, presumably as a way to cope with his ordeal. He also offers a beer to a woman who has suffered a loss. Many characters smoke cigarettes, including a pregnant woman (though other characters scold her for it).