The Quraan says to not commit Zina, and Zina of the eyes and heart such as looking at bad pictures/graphics Knowingly is Zina in itself.
You do not have to have intercourse or cheat on your spouse to be an adulterer.

Speaking from experience, anime/manga etc have a lot of nudity/graphics that is akin to pornography, the females are portrayed as sexy and dress in sleazy clothing/attire or none at all. The Japanese think this is not considered nudity because they are not "human" and they are magical beings or whatever else.

Considering the Japanese/koreans etc do not even believe in Allah or any God for that matter, for them of course, it is fun and okay. But what you may consider as a temporary innocent fun may actually be detrimental to your life, deen and relationships.

Their bodies however are shaped voluptously and not realistically which twists the reader into fantasizing about the characters etc.
The men too in many cases. This is a big thing.

Even in "clean" anime etc there is some nudity/provocative images. There is tons of cursing/demeaning people, and violence in the martial arts animes/mangas, aside from anything else I have not mentione

This is far from what you read in the Quran.

Aside from all the kufr, magical powers, immortal beings, supernatural beings, shayateen etc
Anime does not bring you any closer to Allah or Islam and instead takes you further from it

For years since my childhood, i used to watch anime/manga until I realized what a childish waste of time it really is...even though you think you may enjoy it, ask yourself, when will it ever matter as iit serves no purpose in your life.

Allah knows best.