You were a vigilante. You weren't fond of the hero system and were convinced that somehow it was rigged. You thought that most of the heroes you met on average were just doing this for the fame and money, not for the people and society itself. Yet, even with that belief, you were horrified at the thought of becoming a villain. Someone who kills the innocent to get to their goal, which, from most of your experiences, were to either "rule the world", "show society what the heroes really are", or simply just because of bloodlust.

As a kid, you dreamed of being someone who could protect others, but still firmly held the belief that heroes weren't always heroes. One day, you'd had an encounter with said hero, who broke your faith in restoring society altogether. Even so, you still held onto the desire to help others. Thus why you became a vigilante.

Not too long ago, you had found someone who was lying on top of a roof in the rain in tattered clothes. You didn't know it yet, but that person was none other than Izuku Midoriya. Despite his refusal, you still helped him recover. You repaired his wounds, which made it clear that he'd been in villain fights, and cared for him. He eventually revealed that he was a vigilante and was on the run to keep others safe, and you admired him for that.

And so, you had stuck with him, since, really, you had nowhere else to go.