Where Yamada Hizashi is the main character because he literally is guys. (And Aizawa too for obvious reasons 😼)
Since we don't know a lot about the boys actual home life and childhood before U.A, I filled in some of the gaps with my own headcannons
Yamada lives with his aunts Rikaru Yamada and Margaux Ivanov(This surname may change). He has Italian and Japanese origins, his father being Italian while his mother is Japanese.
His parents had always been.. gold diggers known to fill their pockets and forget about everything else; his father a famous fashion designer while his mother a former ballerina, they were hoping for a girl but.. they got him. And he wasn't exactly right, neither one nor the other (Intersex). Disheartened but determined to make their cash cow they raised him like a girl for about 8 years of his life.
8 years of neglect, abuse and an unruly training regimen to nurture ballet into him, eventually, due to charges against his father for sexual assault of his workers and financial scams, light was shed on his situation, and he was removed from the household to live with his aunts
Rikaru is his father's half-sister, Italian and Japanese in heritage like Hizashi while Margaux is close with Rikaru and helps take care of Yamada, French and Russian in heritage.
Even after being taking away from his parents their harsh critique and ridicule still stays with Yamada for years, the first step in his habit of hiding his emotions. Now not forced to appear feminine, naturally he condemns any femininity and tries his hardest to go by 'boy rules', like 'Boys dont cry'.
Obviously, this affects him in the future.
This makes him quite unbearable in middle school as he's always trying to prove that he's the manliest coolest guy ever. At 13 is also where he meets a special someone with an erasure quirk and follow him about till the other succumbs to being kidnapped by the extrovert.
By high school, those intrusive thoughts are less prevalent, to a degree I mean he doesn't mind wearing hair clips or always dressing super masculine, but behaviour aspects still remain (Like like not letting sadness or negative emotions get to him, this unfortunately bulds into anger issues)
Around this time is also when he gets diagnosed with ADHD.
When entering U.A, Oboro joins their little duo via AIzawa being his in his neighbourhood and also pestering the poor introvert into friendship.
This is really where Yamada starts breaking sown some of his emotional walls and if things had continued down that path he probably wouldn't be as bad as he gets in the future howver, Oboro dies.
And he doesn't know how to handle it, he wants to cry wants to grieve but he cant. Not only because of the ideals he made for himself but also just how his quirk goes haywire when his emotions are all over the place.
This only gets worse when after graduation Aizawa ghosts everyone including him and he feels so completely alone. He gets into college for teaching, is working on his agency and his radio station everything he's wanted but he feels empty, behind that present mic persona is someone so.. empty..
Until 4 years after graduation(21-22 years old), he needs to work on a top secret misson to bust some kind of drug scheme where the rich guys behind it are at some sort of party (this isn't fully planned out but tell me you see the vision) and he needs to go undercover wth someone else as a couple and I think you all know who that is.
The mission goes well enough but after it, Yamada couldn't just let Aizawa go just like that. He couldn't. There's a awakward volley of questions, 'hows life been, do you have a place to stay, agency?.' which ends in Aizawa crashing and Mic's place and their relationship slowly rekindling their relationship..
That's Yamada's part at least. Aizawa's coming soon.
