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.
Deku might be completely shocked at first. Since Bakugou has always been so aggressive towards him, he would never expect such a confession. He might just stand there, mouth agape, not knowing what to say.
Some characters might try to understand Deku's motives. Kirishima, who was close to Bakugou, would be angry at first but might also try to find out if there were any extenuating circumstances. However, many would be afraid of Deku, seeing him as a threat now that he has killed one of their own.
Deku might be initially shocked. He's used to Bakugou's aggression, but an actual injury is different. He could be in pain and disbelief at first. Then, he might try to downplay it, especially if he doesn't want to cause trouble for Bakugou, because Deku is generally a very forgiving character.
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.
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.
Well, Iida would probably have a very proper reaction. He might give Bakugou a stern talk about treating Deku right and being respectful on the date. Mina would be super excited and would start gossiping about it right away. She'd be all over Deku, asking him what he was going to wear and things like that. And Kaminari would probably make some silly jokes about it, like saying Bakugou was finally 'going soft' for Deku.
I think it's hard to say for sure. There are a few characters who could potentially be the traitor, and it's all part of the mystery and suspense of the story.
One possible motive could be a long - held grudge that has festered over time. Maybe Bakugou's constant bullying in their past finally pushed Deku over the edge. Another could be some sort of mind - control or dark influence that made Deku act out of character.
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.