Here's a breakdown:
* Seinen manga (青年漫画, literally "young man manga") is a genre of Japanese comics aimed at young adult males.
* While not exclusively adult-themed, it often features more mature content, including:
* Complex plots and characters
* Realistic portrayals of adult issues
* Violence, sexuality, and darker themes
* Examples of seinen manga include:
* Berserk: A dark fantasy about a mercenary with a cursed sword.
* 20th Century Boys: A mystery about a group of childhood friends who face a global threat.
* Attack on Titan: A post-apocalyptic action series about giant humanoid creatures.
Note:
* There is also "seijo manga" (成人漫画, literally "adult manga"), which is specifically designed for adults and typically features explicit sexual content. This is the closest equivalent to "adult comics" in Western terminology.
* "Shōjo manga" (少女漫画, literally "girl manga") is aimed at young girls and often features romantic themes, while "shōnen manga" (少年漫画, literally "boy manga") is aimed at young boys and often features action and adventure.
It's important to remember that the boundaries between these genres can be fluid, and some manga may blend elements from different categories.