While nothing explicit is shown or said, at one point, a young girl tells the player that another character has been telling her "age doesn't matter when there's love."
A major moment involves the creation of a drug made from human brains. Humans are harvested in filthy conditions, and children are seen to be brainwashed.
While "excessive" is highly subjective, it's worth noting that some environments have large bloodstains on their floors and walls, some offscreen violence is conveyed through large blood splatter effects, and certain attacks make demons explode.
On certain routes, you must battle one of your previous party members, and once she is near defeat, she slices her own neck with a sword, killing herself.
Guns are used and shown by many people throughout the game, along with there being a "gun" element of attacks that the player, enemies, and demons can use
It's not shown on-screen, though the backstory involves ICBM's being launched throughout Earth in a war. One DLC fight takes place as one is heading for Tokyo and the player has a limited number of turns to win the fight and prevent the ICBM from impacting Tokyo