As Izuku gets bullied for something the believes that he didn't have one day he turned evil and shoto up everyone except for Katsuki due to him being on a family trip as Izuku shot up the school and soon enough he left and went on a rampage at the age of 16. Inko was upset to hear what Katsuki has done along with the school now since it's been shot up. With Katsuki he told he parents the truth of what he did as he now felt bad for what he did and turned someone into a villain due to the aggressive nature towards his former best friend as he told Inko about it that led to him doing it. Soon after a year Izuku  finally got caught by the hero's as they learned about what has happened and asked him if he wants to turn over before it got worse and they finally came to an agreement and allowed him to join. During the year Katsuki told Nezu and Aizawa what happened as to how he gotten to that point and that he also told 2-A about what he did that led to him killing people as they despise him for it. As Izuku shows up to Ua a certain girl was able to calm down and soon they started to date until she cheated on him with another guy that led him to killing but he didn't get to yet due to Aizawa being there and stopping him as he saw it as well and took him away and gave him to Momo who was the second person he trust as a girl/women(sorry if most of you wanted to be called a women at the age of 18) soon after a while Momo has gained his affection and moved slow in the now call love relationship with Izuku since she also had a crush on him.

Ship:

Former: Izuku x Camie

New ship: Izuku x Momo