Bakugou katsuki wouldn’t consider himself friends with deku, if you asked him. By all accounts, he should be nothing more but a bully to Izuku Midoriya. The only issue? Bakugou is still very much attached to Izuku in a weird way, and hates the idea of Izuku being with anyone. And for a reason he just cannot explain, he was absolutely livid at finding out that Izuku had a new “friend”. Seeing Izuku with a new friend made him feel like he was being replaced. Izuku was his. Not anyone else's.