An interesting plot for a Super Smash Bros Brawl OC fanfiction could involve an OC that is a master of disguise. This OC can transform into any of the existing Smash Bros characters, but with a twist. Their abilities are a bit different from the original characters. They use this power to create chaos during battles, making other characters suspect each other. As the story progresses, they start to have a change of heart and end up using their power for good, helping the Smash Bros community deal with an outside threat that none of the regular characters can handle alone.
One idea could be a story where all the characters from different universes team up to face a new, unknown threat that is causing glitches in their worlds. For example, Mario, Link, and Pikachu working together in a way they never have before.
One idea could be a story where all the characters from different universes in Super Smash Bros Brawl team up to fight a new, powerful and unknown threat that is disrupting the balance of their world. For example, a strange dark energy is starting to corrupt the stages and they have to find the source and stop it.
One idea could be an OC from a relatively unknown game getting invited to the Smash Bros universe. They have to learn the ropes of the unique fighting style there. Another could be an OC who has a special power that disrupts the balance in the Smash Bros world, causing both chaos and new alliances among the characters.
One idea could be an OC from a little - known game series getting invited to the Smash Bros world. They could start off as an underdog, struggling to adapt to the intense battles and different fighting styles. But as the story progresses, they learn from the veteran Smash characters and develop their own unique combat techniques, eventually becoming a respected fighter in the Smash universe.
A fan fiction could explore the backstories of some of the less - known characters in Smash Bros Brawl. Maybe the story could focus on how a particular character got their unique abilities and what their life was like before being part of the Smash Bros universe. It could be really interesting to see how they trained and developed their skills in their original worlds.
A plot could revolve around a new character being added to the roster secretly. This character has an unknown power that starts to disrupt the balance in the Smash Bros world, and the other characters must figure out who it is and stop them. For example, this new character could be causing glitches in the battle arenas, making it difficult for the regular characters to fight.
One idea could be an OC who has a unique fighting style that surprises all the Smash Bros characters. For example, an OC that can manipulate time during battles, freezing opponents momentarily or speeding up their own attacks. Another could be an OC from a different dimension who enters the Smash Bros world to find a way to save their own realm. They would have to learn the rules of the Smash Bros battles and form alliances with some of the characters.
I'm not sure specifically which one is the longest 'Super Smash Bros. Brawl' fanfic. There are likely many fanfics out there, and it would require a lot of research in the various fanfic platforms to determine the absolute longest one. It could be a complex, multi - chapter epic that delves deep into the game's characters, their relationships, and the battles in the Smash Bros. universe.
To create a unique OC for Super Smash Bros Brawl fanfiction, consider their appearance. Make it distinct from the existing characters. Maybe they have a robotic body with living plants growing out of it if you want to combine nature and technology. Their personality is also crucial. Are they a cocky fighter who taunts a lot, or a more reserved and strategic one? Their backstory should tie into their personality and abilities. If they have a tragic past, it might explain why they fight so aggressively or defensively. And don't forget about their fighting style. It should be something that stands out, like a character who fights using only their feet or a character who uses psychic powers to control the stage elements.
One idea could be a crossover within the Smash Bros universe. For example, characters from Star Allies team up with unlikely allies in the Smash Bros world to face a new, powerful threat that combines elements from both games. Maybe a villain who can manipulate the power - ups and stages in a strange way.