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.
Character development is a big part of these fanfics. Since both characters have their own fan bases, the writers try to stay true to their original personalities while also adding new layers. For example, Garou's struggle between his anti - hero ways and his potential for good can be further explored in relation to Metal Bat's more straightforward sense of justice. And the action scenes in these fanfics are usually intense, given the combat - ready nature of both Metal Bat and Garou.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, and there are likely to be quite a few 'garou x metal bat' ones there. Just use the search function and type in the relevant tags.
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.
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.
There is also 'Metal and Fang'. In this fanfic, it focuses on how Metal Bat and Garou start off as rivals but gradually come to understand each other's motives. It's quite interesting as it delves deep into their personalities and how they might interact in different situations.
There's a fanfic titled 'Garou and Metal Bat: A New Understanding'. In this story, they start off as rivals but as the plot progresses, they realize they have more in common than they thought. It shows their journey from hostility to a sort of friendship, with some great action scenes in between.
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.
One possible plot could be that the Child Emperor, with his high intelligence and various inventions, is initially intrigued by Garou's self - proclaimed 'hero - hunting' ideology. They might have a series of battles where the Child Emperor uses his technological gadgets to counter Garou's martial arts skills. Eventually, they could find some common ground in their views on the nature of heroes and villains, leading to an unexpected alliance or at least a mutual understanding.
It's really hard to say. The Child Emperor has his amazing technology and intelligence on his side. He can create all sorts of gadgets to attack and defend. But Garou is a really tough fighter with great martial arts skills and the ability to quickly adapt in battle. If the fight is in an open area, Garou might be able to use his speed and agility to dodge the Child Emperor's attacks and get close enough to land a powerful blow. However, if the Child Emperor has time to set up his defenses and traps, he could potentially wear Garou down. So it could go either way depending on the circumstances of the fight.