The main characters would likely include Kirby. Kirby is known for his cute appearance but powerful abilities. He could be caught in the middle of the civil war or choose a side based on his own simple yet strong sense of right and wrong. Then there's Pikachu. Pikachu is extremely popular and his electric powers could be a great asset in the battles of the civil war. It could be siding with the group that wants to protect the Smash Bros world from chaos or be part of a group that wants to change the existing order.
The plot could revolve around a power struggle. There could be a new power source or a special item that has emerged in the Smash Bros world. Different characters have different ideas about how to handle it. Some want to use it to gain more power and control, while others believe it should be destroyed or shared equally. This causes a split and a civil war breaks out. For instance, if there was a new power - up that could make a character invincible, characters like Bowser might want to hoard it, while Mario would want to share it among everyone.
Mario, Link, and Pikachu are some of the main characters. Mario is from the Super Mario series, Link from The Legend of Zelda, and Pikachu from Pokémon. They are very popular and often play important roles in the battles.
The more heroic characters like Marth and Ike would be deeply affected. They are used to fighting in a more 'honorable' way. But against Thanos, they would have to consider using more underhanded tactics. And the characters from the Animal Crossing series, like Isabelle, would be completely out of their depth. They are used to a peaceful life and would struggle to face Thanos' menacing presence.
One possible plot could be that Thanos somehow enters the Super Smash Bros universe. He could be after the Smash Bros' power sources or something equivalent to the Infinity Stones in their world. The heroes from various game franchises in Smash Bros would have to team up to stop him. For example, Mario and Link might work together to find a way to defeat Thanos' powerful attacks.
Black Widow would rely on her agility and combat skills. She could have quick, multi - hit attacks like some of the faster characters in Smash Bros. Her special moves could include things like her Widow's Bite for a stun effect. Captain America, with his shield, could have a good balance of offense and defense. His shield throws could be ranged attacks, but he also needs to be vulnerable when he throws it, like in the actual Smash Bros. game where characters are exposed after certain attacks. This way, his power is not too overbearing.
Dark Samus can be a central figure in fanfiction. Her dark nature stands out among the Smash Bros cast. She might be used to introduce new challenges for the other characters. For instance, she could disrupt the normal Smash Bros tournaments in the fan - made stories.
Mario is often a popular choice. He's such an iconic character that people love to write about his adventures in the Smash Bros world. His relationship with other characters, like Luigi or Peach, can be explored in many ways.
Bakugo is also a favorite. His explosive personality and powerful quirk add a lot of drama and action. In the fanfictions, he often has intense rivalries with other Smash characters.
A unique plot. For example, if it combines the different universes and characters from Super Smash Bros and Infinity War in a way that's unexpected. Maybe having characters from Super Smash Bros interact with the Infinity Stones in a creative manner.
Mario is extremely popular in Super Smash Bros fanfics. He's a classic Nintendo character, and fanfics often explore his leadership role among the Smash Bros crew. Writers might create stories about his adventures outside of the normal Smash Bros battles, or his relationships with other characters like Luigi.