Well, the number of story missions in My Hero One's Justice 2 is not fixed. Generally, there are approximately 25 to 35, but this can change based on expansions and patches.
In 'My Hero One's Justice Full Villain Story', the main characters are surely the villains. We can expect to see Tomura Shigaraki at the forefront. His journey to become a powerful villain and his hatred for heroes are key aspects of his character. Dabi, with his mysterious past and his destructive fire - based quirk, is likely to be another main character. Himiko Toga, the blood - thirsty and shape - shifting villain, would also be an important part. There could be other villains too, perhaps those who are part of villain organizations and have their own unique quirks and motives that will be explored in this story.
The story likely focuses on the villains in the My Hero Academia universe. It could show their backstories, motives, and how they interact with each other and the heroes in this 'full villain' narrative.
Fanfictions related to Stain from 'boku no hero academia' can vary greatly. Some might depict him as a more sympathetic character, trying to understand his motives for his extreme actions. Others could be more action - oriented, with Stain engaging in battles that we didn't see in the anime or manga. There's also the possibility of exploring his backstory further, like his early days and what led him to become the character we know.
I'm not entirely sure as there could be various interpretations. It might involve the hidden backstories or events related to the heroes in a particular 'one hero's justice' universe. Maybe it delves into their personal struggles, past traumas, or undisclosed motives that drive them to seek justice.