'The answers you needed.'

Katsuki did bullied Izuku in the past, and now at U.A they were known as the dating inseparable couple. All Izuku did was ask questions but Katsuki would ignore him by making an excuse or walk away. Until one day, Izuku unlocked his new quirk he couldn't help but to not control it and then in the end the quirk was controlling him, turning himself into a villain.