A new character could be created as the main antagonist. This character could be a being from a dimension that has been observing both the Asura's world and the Street Fighter universe. It realizes that by causing conflict between the two, it can absorb the energy of destruction and chaos. So it starts manipulating events, pitting Asura against the Street Fighter characters at first, and then revealing itself as the true source of all the problems.
One possible plot could be that Asura finds himself in the Street Fighter universe due to some mysterious rift. He then gets involved in the various battles and rivalries. Maybe he initially clashes with Ryu, thinking he is a threat, but later they realize they have a common enemy that is causing chaos in both their worlds.
The plot could involve a tournament in the Street Fighter world where Asura is an unexpected entrant. His over - the - top powers would shock the other fighters. Maybe some of the Street Fighter characters would be intrigued by his raw power and try to learn from him, while others would be jealous. This could lead to various matchups and character development for both Asura and the Street Fighter cast.
Asura's superhuman strength could be combined with Ryu's Hadoken. Imagine Asura powering up a Hadoken with his raw strength, making it an even more devastating attack. It could be like a super - charged projectile that could break through multiple defenses.
Perhaps in the crossover fanfiction, the dark energy in the Mass Effect universe has some strange effect on Asura. It either amplifies his wrath to uncontrollable levels or gives him new powers. Meanwhile, the Asari, with their biotic abilities, try to form a connection with Asura to understand his nature. This connection could lead to a mutual understanding between Asura and the Mass Effect races, and together they work towards a common goal, like saving a planet that is on the verge of destruction due to a combination of Mass Effect threats and something related to Asura's past.
Luffy from 'One Piece' could also be an interesting crossover. Luffy's stretchy abilities combined with Ryu's martial arts would make for some unique fight scenes. They could also learn from each other's determination and loyalty to their friends.
An ancient evil that was once sealed away could see the reborn dragon sin of wrath as a key to its release. This entity might manipulate events and characters from the shadows, setting up traps and challenges for the sin of wrath. It could have a long - standing grudge against the sins in general and wants to use the new - born one to exact revenge on them all.
Another option is to check out Reddit. There are subreddits related to Asura's Wrath where fans might share or discuss crossover fanfictions. You can also post a request asking if anyone knows where to find good Asura's Wrath crossover fanfictions. However, make sure to follow the subreddit rules while doing so.
One popular theme is the crossover with other action - based video games. For example, a crossover with God of War could be interesting as both have powerful and somewhat angry protagonists. The clash of their worlds and fighting styles would make for an exciting story.
Asura is surely a main character in this fanfic. Besides, characters like Piccolo could also be important. Piccolo is a powerful and intelligent character in the DBZ universe. He might play a role in dealing with Asura's wrath, either as an ally or an adversary depending on how the story unfolds. Also, there's a good chance that other Saiyans like Gohan could be main characters as well, since they are key figures in the DBZ world and their reactions to Asura would be interesting to explore.
It could be a jealous neighbor who doesn't like the Dalmatians or Hansel. This neighbor might try to cause trouble for them, like spreading false rumors or trying to get the Dalmatians removed from the street.