In a fanfiction, the aliens could capture Naruto and try to study his unique abilities. The monsters then decide to rescue him because they realize his powers could be the key to defeating the aliens once and for all. The story could involve a lot of action as the monsters infiltrate the alien base to save Naruto.
In the Monsters vs Aliens original story, a young woman is transformed into a giantess after being hit by a meteor on her wedding day. She is then taken to a secret government facility where she meets other monsters like a half - ape, half - fish creature, a gelatinous mass, and an insect - like monster. When aliens attack the Earth, these misfit monsters are the world's only hope. They use their strange powers and abilities to combat the technologically advanced aliens and ultimately protect the planet.
Power and its consequences is also a theme. The OC may have some special power, and the fanfiction explores what they do with it. They could use it for good, like helping the monsters protect the Earth, or it could lead them astray if they misuse it. This theme adds depth to the story and the character of the OC.
The main characters include Susan Murphy, who becomes Ginormica. There's also The Missing Link, B.O.B., and Insectosaurus. And of course, the alien villain Gallaxhar.
One idea could be a story where the monsters and aliens have to team up against an even greater threat from another dimension. Maybe a powerful interdimensional being that wants to conquer both Earth and the alien planets.
In Naruto Monsters vs Aliens fanfiction, it's hard to say who would win. Naruto's monsters have unique ninja abilities like chakra control and powerful jutsus. However, aliens might have advanced technology and strange powers. If the aliens' technology can disrupt chakra, they could have an advantage. But Naruto monsters are used to fighting in their own world's crazy battles.
The Missing Link is also quite popular. His brash and confident personality can add a lot of humor and action to a fanfic. He could be on a quest for glory or trying to prove himself to the other monsters.
One plot idea could be that aliens invade the Naruto world seeking a powerful energy source, which is actually the chakra. The Naruto monsters then team up to defend their world. Another could be a group of Naruto monsters getting accidentally transported to an alien planet and having to fight their way back home. They could learn new techniques from the aliens they encounter during their journey.
The relationship might start with curiosity. The OC could be curious about Susan's abilities and Susan could be interested in the OC's origin. As they start to communicate and work together on small tasks, like helping the monsters train for a potential threat, their relationship gradually deepens.
Perhaps the OC is initially distrusted by Susan and the other characters. But as the story progresses, through various adventures and challenges, like facing a powerful alien invader, the OC proves their worth and they form a strong bond with Susan. They might have to combine their unique skills, Susan's size - changing ability and the OC's special weapon or power, to defeat the enemy.