When it comes to manga and anime, whether it's safe for younger fans is often debatable and at the discretion of the adults in their lives. Despite sharing visual similarities with American comics and cartoons, manga and anime tend to address a lot of mature themes, even when the characters are middle or high school-aged. When it comes to Koyoharu Gotouje's Demon Slayer: Kimetsu no Yaiba, the very title should be a bit of a warning.
Source：https://www.cbr.com/demon-slayer-age-rating-guide/
