The relationship could start with hatred. Bakugou may initially be enraged that Deku has become a villain. But as time passes, he starts to see the reasons behind Deku's transformation, which could lead to a more complex relationship.
One concept could be that Villain Deku manages to manipulate Bakugou into joining his side. Maybe he plays on Bakugou's insecurities or his desire for power. Another could be a world where they are both villains from the start and they form a power - hungry duo, causing chaos everywhere. A third concept might be that Villain Deku kidnaps Bakugou as part of a grand scheme to get back at the hero society that they both feel has wronged them in some way.
Well, AO3 is definitely a great place to start. It has a tagging system that makes it easy to find the specific type of fanfic you're looking for. When you search for 'villain deku x bakugou', you can also filter the results by things like rating, word count, and completion status. Fanfiction.net also has a decent selection. However, you need to be a bit more careful there as the quality control isn't as strict as on AO3. You could also look into Tumblr. There are a lot of My Hero Academia fans on Tumblr who might post about or recommend good villain deku x bakugou fanfics. Some of them might even have their own fanfic blogs where they share their work.
To develop their relationship realistically, start with their existing dynamic. Bakugou is often aggressive towards Deku, so a slow change is needed. Maybe have them be forced to team up. As they face challenges together, Bakugou could start to respect Deku's abilities bit by bit. For example, if they are in a battle against a powerful villain and Deku comes up with a clever strategy, Bakugou might grudgingly admit Deku's smarts.
It could start with Deku taunting Bakugou. As a villain, Deku would have a new - found confidence and would use it to get under Bakugou's skin. He might leave cryptic messages for Bakugou, hinting at their past and how Bakugou used to bully him. This would make Bakugou angry but also curious about what Deku has become.
One idea could be that Deku, turned villain, challenges Bakugou's view of heroism. He could expose the flaws in the hero society that Bakugou blindly believes in. For example, Deku might target the way heroes are ranked and how it creates a cut - throat environment. This would force Bakugou to re - evaluate his own pursuit of being the top hero.
A possible plot is a power struggle between them. Since Deku has turned villain, he might see Bakugou as a threat to his plans. Bakugou, on the other hand, wants to bring Deku back to the light. This creates a constant back - and - forth of battles, both physical and psychological, as they try to outwit each other.
One great Bakugou x Deku fanfic is 'Unlikely Allies'. It explores their relationship in a post - war scenario where they have to work together to rebuild society. The character development is really well - done.
You can start by looking on popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics for various fandoms, including those related to Todoroki, Deku, and Bakugou. The search function on AO3 allows you to easily filter for the specific relationship you're interested in.
Bakugou could use his words. He might tell Deku that he believes in him. For example, he could say 'Deku, you may be a nerd but you're a strong nerd.' It's a backhanded compliment but it shows he has faith in Deku.