(I got the picture from Pinterest but the artwork says the artist is @wenywenychim.) Izuku and Bakugou always were really close since they were 2. Bakugou got his Explosion quirk and a week later Izuku got his Fire Manipulation quirk. Bakugou hated how Midoryia was almost equal to him. So Bakugou stayed close to Izuku but still bullied him every now and then. He didn't want Izuku to become the #1 hero because if that happened then Katsuki wouldn't be the best, he would be tossed to the side and forgotten by Midoryia. Or worse, Izuku would go against villain after villain until he died from his stupidity. Bakugou knew Midoryia was like a damn golden retriever, caring about everyone but himself. Izuku on the other hand, was stupidly clueless. He never saw those worried and concerned side glares that Bakugou gave him. Midoryia just thought that Katsuki was being intimating or mad. But Izuku still cared about his childhood friend more than anything, Bakugou was his best friend although they rumbled sometimes they still got along. They probably got along because they shared a huge apartment with each other and 4 other roommates, and Izuku was sharing a room with Bakugou. This happened after graduation because Kirishima and Denki wanted to get this huge apartment that was close enough to everyone's agencies. So they asked some classmates if they wanted to get the apartment together and Jiro, Izuku, Bakugou, and Uraraka (of course) agreed.