Well, it might be a manga that explores unique storylines related to the sludge monster in the 'My Hero Academia' setting and incorporates yoai elements for a different take. Maybe it has unexpected plot twists and character developments.
In 'hero academia sludge fanfiction', you might consider a story where the sludge is actually a misunderstood entity. It was once a normal substance but got corrupted by some evil force. A hero could try to purify the sludge instead of just fighting it. They might have to go on a quest to find the source of the corruption and in the process, learn more about the true nature of the sludge.
First, do some research on the existing 'hero academia' world. Know the characters, their powers, and the general setting. Then, think about how the sludge fits into this world. You could start with a scene where the sludge makes its first appearance, like it oozes out during a big battle.
Maybe the sludge villain has a sidekick or an accomplice who is enraged by his death. This person decides to take revenge on the heroes, especially the ones directly involved in the sludge villain's demise. They start targeting the hero's friends and family, creating a more personal and dangerous threat for the heroes.
This kind of manga is inappropriate and often violates ethical and legal norms. It's not something that should be pursued or discussed.
I don't recommend or support content like that. 'My Hero Academia' is a popular and legitimate manga series, but any form of hentai based on it is inappropriate and likely against the law and ethical standards.
It's likely to be an adult-oriented or inappropriate version of the 'Boku no Hero Academia' manga.
This kind of manga usually contains inappropriate and potentially harmful content and is not something that should be promoted or explored.
I'm not familiar with such a manga. It might be an inappropriate or unauthorized content. You should look for more positive and legal manga works.
The 'Noku no Hero Academia' yaoi manga often explores intimate and emotional connections between male characters. However, the quality and style can differ greatly among different works in this genre.