Izuku was always shamed on for being quirkless, it got to the point that it was normal. 

He was used to it.

So he decided to just ignore it and focus on his passion - strategizing, analysing, and coding. 

After years of sharpening his skills, he was most likely a genius among geniuses - well at least for a kid his age 

One night he accidentally hacked into where the league of villains contains files on hero's and enemy's. That's when the annoying cat and mouse game started...

Ever since that day the league of villains have been trying to convince him to join them after finding out about his "potential". As we know Izuku, someone who loves hero's declined every single time they "asked" (bothered) him. 
They couldn't even threaten or kidnap him because
 
1. He has nothing they could threaten him with, after Inko Midoriya (Izuku's mother) died. He had nothing to live for, yet he still try to stay alive the best he could. Never less he wouldn't care less if he was killed or died. 
and 
2. He has a sharp knife in his mouth just for killing himself if it was needed. 
For example - if he got kidnapped

Things started to get worse when he entered U.A as a gen.ed student.
The league started to show up more, chaos happened.

"Sorry my description isn't that good, writings not my strong point - author"
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