For a good character interaction between Garou and Saitama, start with their fundamental differences. Saitama is a hero who is bored with the lack of challenge, while Garou hates heroes. Have them start with a fight, but make it a comical one where Saitama's nonchalance annoys Garou to no end. This can lead to some great dialogue exchanges where Garou tries to taunt Saitama into taking him seriously, but Saitama just doesn't care.
Well, in the fanfiction, the moment when Cosmic Garou tries to counter Saitama's attacks with his own new - found cosmic powers is really exciting. He has evolved to a whole new level, and seeing how his powers match up against Saitama's is a big part of the thrill. Maybe he creates some sort of cosmic energy blast that Saitama has to dodge or block in an unexpected way.
The battle between Saitama and Cosmic Garou in the fanfiction would have a catastrophic effect on the environment. First, Saitama's initial attacks might send out concussive forces that uproot trees and scatter them like matchsticks. Cosmic Garou's response could involve creating some sort of cosmic vortex that sucks in everything around it, from small pebbles to large boulders. As the fight progresses, the area around them would become a desolate wasteland, with fires raging from the heat generated by their attacks and the air filled with dust and debris, making it difficult for any living thing to survive in the vicinity.
Saitama is a very powerful hero in the One Punch Man universe. He can defeat any opponent with just one punch. He has a simple appearance and a somewhat laid - back personality.
Yes, there might be. The Naruto and One - Punch Man fandoms are both large, and it's not uncommon for fans to create crossover fanfics. In such a fanfic, Naruto could be depicted as a fan of Garou for various reasons, like being impressed by his fighting style.
One idea could be a story where Garou and Metal Bat are forced to team up against a common enemy stronger than they've ever faced. They start off hating each other but gradually learn to respect each other's fighting styles.
Sometimes King is paired with Saitama. King, known for his false reputation of being a super - strong gamer in the original story, could be in interesting interactions with Saitama in the fanfiction's gaming context. Maybe they compete in a gaming tournament within the fanfiction, and Saitama's effortless wins baffle King.