Well, the fanfiction could focus on a training arc between them. Imagine Garou, who has his own unique fighting style, teaching Metal Bat some new moves. In return, Metal Bat could teach Garou about the importance of protecting the weak. Their relationship could develop from a mutual dislike to a begrudging respect and then to an actual friendship. This could lead to them fighting side - side against the various threats in the One Punch Man universe, and they might even change the public perception of Garou from a villain to an anti - hero.
A plot could be that Garou, after one of his defeats, is found by Metal Bat. Metal Bat decides to take Garou under his wing, much to the surprise of everyone. They could then have adventures where they encounter different heroes and villains. Along the way, Garou might struggle with his old ways of thinking, and Metal Bat would be there to nudge him in the right direction. Their friendship could be tested when they face off against some of Garou's former allies who don't approve of his new path.
The plot could be Metal Bat going on a quest to find a special metal to upgrade his bat. Along the way, he encounters various monsters and other heroes. He might have to compete with other heroes who also want the special metal for their own reasons.
One possible fanfiction could be about the Metal Bat facing an extremely powerful and unknown monster in the One Punch Man universe. He could struggle in the fight at first, using his bat with all his might. But as the battle progresses, he discovers a new level of strength within himself, inspired by the other heroes he has seen in action.
In the original story, Metal Bat is more of a hero and Garou a villain. In fanfiction, their interaction could be more complex. Maybe they start as rivals but then find common ground in their love for a good fight. So instead of trying to defeat each other for good or bad reasons, they might fight just for the sake of testing their limits and then walk away without any hard feelings.
The plot could involve Garou somehow ending up in Saitama's world more permanently. Maybe he decides to team up with Saitama against a common enemy. This new enemy could be a powerful being from another dimension that neither of them could face alone. Their contrasting fighting styles would make for an interesting dynamic, with Saitama's one - punch power and Garou's martial arts skills.
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.
Fanfiction explores Metal Bat's character by delving into his emotions. For instance, his anger, which is a big part of his fighting style, can be explored in more detail. We might see what really makes him tick and what can push him over the edge. His loyalty to his sister is also a key aspect. Fanfictions can show how this loyalty affects his decisions as a hero, like whether he'll abandon a mission to protect her.
One popular storyline in Metal Bat fanfiction could be his adventures outside of the main One Punch Man plot. For example, he might go on a solo mission to a far - off land to fight a new and powerful monster. Another could be his interactions with other heroes in a more in - depth way, like training sessions with Genos or team - up missions with Mumen Rider. And sometimes, fanfictions explore his family life, like how he balances his hero work with taking care of his sister.
One idea could be that they start off as rivals but are forced to team up against a common, even more powerful enemy. As they fight side by side, they gradually gain respect for each other's fighting abilities.
How about a plot twist where Garou suddenly loses his powers. Metal Bat, who has always seen Garou as a powerful adversary, now has to protect him. This forces them to work together in a new way and also makes Metal Bat re - evaluate his perception of Garou.
Another role could be as an antagonist. Maybe they have a different view on how heroes should operate and end up causing trouble for the other heroes. This would create conflict and drive the plot of the fanfiction forward.