Disclaimer: I do not own Nintendo or the Super Smash Bros. Series. If I did, then Mewtwo, Roy, and Pichu would be in Brawl with no Snake or Sonic to rape the game with horrible encounters online.
In this world, there is an uncommon mineral known as "smashite". Smashite has a nonmetallic luster with a hardness of 1. Smashite has no known uses other than the creation of a certain item known as a smash ball. Smash balls are items in Super Smash. Bros. Brawl that float around the stage for a certain period time during a match, waiting to be broken. When broken, a rainbow flame appears around the person who broke it. Even breaking a small crystal of smashite can do the same. This person is granted almighty power for an amount of time when the power is unleashed. This is known as a "Final Smash".
A few months after the defeat of Black Shadow and Blood Falcon, the well-known Captain Douglas Jay Falcon thought he had finally finished his job. But there was another notorious clone of him. Remember Captain Falcon's white and pink costumes based on Jody Summer's clothes? That's exactly what he looked like. You taunt-match players know him as Captain Fabulous. But his name is Faptain Calcon, which sounds many times more horrible. Faptain Calcon is much more horrible than the likes of Black Shadow and Blood Falcon combined. By the many that knew of him, he is referred to as "the clone straight from hell" or "Satan himself disguised as Captain Falcon".
Captain Falcon had several bloody battles with this clone of his. One day, our beloved captain believed that he had completely defeated Faptain Calcon with a Falcon Punch using all of his might left in their gruesome battle with some help from his fellow smashers. A few years later (present-day), Faptain Calcon returns. This time he has retrieved an item created by the evilest of scientists with immense power known as the Smash Sphere to create a dangerous army with mysterious powers.
Faptain Calcon and his army later attack an urban city (which is now a ghost town) rumored to have smashite in a large amount. This city is said to have the most amount of smashite in the whole wide world. Meanwhile, Captain Falcon and his fellow smashers team up to fight back against this mysterious army.