you had a childhood friend but you used to bully him. One day he went missing and you never saw him at school. You one say found a cute fluffy green dog that reminded you of izuku so you took him home and named him after your friend/person u used to bully. The dog kept trying to escape but he one day gave up and got close to you after a month. One day you came home to see your missing friend izuku laying on your bed watching tv

"Ah! Kachann! Your home early!!"

he seems nervous