Izuku was born without a quirk, which is highly unusual. A quirk, or super power, is something that everyone has. However, Izuku is an anomaly. He's unable to do anything special, and this makes him different from others in a negative way. He's treated as an outcast, often being shunned and bullied by others. This leads to Izuku developing insecurities and a low self-esteem. He struggles to believe in himself and to stand up for himself. He often feels alone and powerless against the world.