48 parts Ongoing Izuku was known to be an only child who was born with no quirk. Despite this set back he still aimed to be a hero, but no one believed in him. No one gave him that time of the day to try and cheer him up, instead they put him down.
He was bullied by his childhood friend for being quirkless, and told he'd amount to nothing, not even his mother had faith in him. It made him feel like it was just him against the world, in order to attain his dreams... except, it wasn't just him.
Did you think All Might was the first to believe in him? You're wrong, it wasn't him. No... it was someone before him. Someone who gave him hope. Someone who cheered him on and kept pushing him forward. Someone he never thought would be his motivation to keep going, even more so, when his quirk 'manifested' late.
After all, she was only a kid...
A kid that played a role so large in his life that when it took a turn, he never expected for her to be the one he'd rely on. The one to brave the world with him.