The main distinction of porn with a story genre from regular porn is the presence of a coherent narrative. Regular porn often jumps straight to the sexual action, while the story genre tries to add some kind of story framework around it. But in the end, both are adult-oriented and feature explicit sexual content.
Well, it's hard to say for sure. The concept of 'porn-like' is quite subjective. Some might consider certain novels with excessive sexual descriptions as such, but it depends on individual perspectives and cultural standards.
In many places, 18+ porn comics are considered illegal. This is because they can have a negative impact on society and violate moral and legal standards.
Ben 110 can be developed by giving him new challenges related to the Highbreed. For example, he could face a Highbreed villain who has a power that nullifies Ben's alien forms. This would force him to rely on his human intelligence and resourcefulness. He could also develop his character by learning about the Highbreed's language and communication methods, which would show his adaptability.
One aspect of 'Ben 10 Evil Ben Fanfic' could be the exploration of the character's dark side. Evil Ben is a fascinating take on the original Ben. It might show how he would use his powers in more malevolent ways, like using the Omnitrix to intimidate or dominate others rather than protect. This could also lead to interesting storylines involving his relationships with the other characters, as they would have to either oppose him or be corrupted by his influence.