After watching an animation video, I decided to write a one-shot explanation way. This will be a crossover with Bleach and Super Smash Bros. I hope you enjoy it, and I own nothing.
Up in another world certain people work together to keep a world at peace. These people are known as Smashers. These are people with special fighting skills and special powers and weapons that are hard for anyone else to use. Thirteen people lead squads of other Smashers to protect the world. These thirteen are no pushovers and are sometimes overlooked as well. Mario, Sonic, Ness, Rosalina, Donkey Kong, Marth, Pikachu, Sheik, Metaknight, Link, Fox, Samus, and Pit have been chosen to lead their squads for certain reasons.
Mario is the head of the entire group. He leads Squad 1 and never backs down from a fight when challenged. He will protect his kind with his very life and leads them with his power of fire.
Sheik is the leader of the second squad. She leads the group through stealth and nature. She uses whatever she can find that could be used against the enemy. She can turn herself into an alternate form that allows her to fight in the battle front with magic as well.
Pit leads squad three and is known for using the air against his opponents. He's the weakest of the captains but has the biggest guts to fight and take down his opponents. He's not afraid to fight to his last breath.
Rosalina leads squad four and is considered one of the most dangerous women. She cares for people by leading a group of people who usually heal people more than fight the enemy. She makes sure people are healed and taken care of. If she is ever threatened she will not hesitate to take down her opponent.
Fox leads squad five and fights for his life to protect his team. He cares about everything especially his wife and will protect his most precious people first. He mostly fights with weapons that he equips himself with but is pretty swift when using his feet in battle.
Link leads squad six with his master sword and triforce of courage helping him. He wields an arsenal of weapons that makes him the man who strategizes to hit his opponent's weak points even if there is only one. He never backs down from a fight and will do all he can to protect his team.
Donkey Kong is the leader of squad seven and is seen as the strongest member when it comes to his natural strength. He uses no weapons in battle and takes his opponents on with no worry about his health. He doesn't care what happens to himself as long as he completes the mission and will protect those who need the protection.
Marth leads squad eight with just his sword. He only fights using his sword and takes down more enemies without using other parts of his body. He specialized in his sword and makes sure that his team is fully prepared for future events against the enemy.
Samus leads squad nine and makes sure they show their work. She fights using her cannon on her arm and uses a gun when not equipped with her armor. She hates being looked at by men but keeps her cool on the battle field when fighting along with her squad.
Ness leads the tenth squad and is the youngest leader of the entire group. He uses a yo-yo and bat as his weapons and has a variety of special attacks. His psychic powers make him a formidable foe, and his heart to protect people will make him even more dangerous than he already is.
Metaknight leads squad eleven and shows no mercy to his enemies. He prefers to stick with his honor and makes sure no one tries to destroy it. He protects his team and makes sure they are not going to lose their honor as well.
Sonic leads squad twelve with his speed. He doesn't care what his men focus on as long as they finish the job on defeating the enemy. He doesn't tolerate if his men question his orders even though he is cocky. He will fight for his team and show them why he's in charge.
Pikachu leads the final squad made up of special fighters. He leads special fighters that are like animals. He leads his squad with a major electric shock and will protect his squad. He's one of the most loyal team members even if he can't speak English like the others.
These thirteen are not to be messed with one single bit. Their enemies will try to destroy them but have failed every time, but they will not stop until they win. Those who go against these Smashers and their followers will not back down fighting their enemies.
Well, ok this is more of an explanation, but that isn't the point. Anyone can make a story off of this if they want to or not. You could change a few things here and there, but I request you do not change the captains. Choosing the captains were a bit hard. I was thinking of changing Metaknight with Kirby and Donkey Kong with Ike. I also questioned having Samus being in the group. Other characters that were close were Pac-man, Greninja, Little Mac, Snake, Kirby, Ike, and Charizard. This was hard especially trying not to have the same thing said over and over for certain characters. Plus, I wanted ech character to clash with some others. R&R?