The violence can range from each game. From animated (Sonic series) to intense/realistic violence (Resident Evil), the series has a variety of intensity.
Mostly Fantasy violence.
Profanity
Severe
Being unscripted, there is non-stop profanity all over the place. "Fuck", "Shit", "Cock", "Cuck" and others are said every few seconds. It's easier to count how long a video will go without a swear word being said. All of it is played for laughs.
Alcohol, Drugs & Smoking
Moderate
Drug References are brief. (Examples include weed and cocaine).
A character says "yes weed just for you" and gives someone shards of a crystal.
Frightening & Intense Scenes
None
The series is pretty light-hearted, but the content can still range from its use of violence and scary scenes.
The devil is a character. But he is goofy and meant to be played for laughs.
A lot of dark humor.
Shadow wants to be the ruler of Hell. This is supposed to be comical.