Naoko Sasaki/Yagi

(The way I completely forgot Sir Nighteye exists and she ended up having almost the exact same quirk as him 😭 please ignore the similarities until I can find something better)

Naoko is the daughter of All Might.

She was born after a random one night stand with a fan. Toshinori is aware of her but he rarely ever sees her and just pays her mother child support.

She knows what Toshinori really looks like from the very few times he spent time with her. Nobody knows he has a daughter and he wants to keep it that way so he refuses to be around her as All Might. He claims it’s for her safety but the truth is that he’s ashamed to have a daughter with a random woman.

Naomi never minded as a child because she idolized her father, but as she got older, she vied for his attention and affection. This lead her to joining the hero course in UA where she ended up in Class 1B.

Her quirk is called “Future Sight”. She is able to see 5 minutes into the future. Because of this, she is able to predict people’s moves before they’ve even thought of it. She has a refractory period of about 7 minutes though and her quirk can only work if she makes eye contact with her target.

She trains so hard because she wants her father to see her as worthy of being a hero, hoping he will allow her to intern with him. 

She starts to notice that her father spends a lot of time with Izuku and she becomes jealous and envious. She passes Izuku in the hallway one day and makes eye contact with him. Unknowingly to him, she saw into his near future and saw him talking to Toshinori about One For All. She had no idea about One For All and she became enraged that her father gave some random loser his quirk when he’s ignored her all her life no matter how hard she tried to get his attention. She notices how he treats Izuku like his own son and this feeds in to her hatred.

During the sports festival, she gets paired up with Izuku. Considering they’re in different classes, he has no clue what her quirk is, giving her an advantage. She’s able to predict all his moves before he even makes them and is able to evade all his attacks. After he has worn himself out, she brutally attacks him. All her training has paid off as she lands blow after blow.

When Izuku is laying on the ground out of breath and weak, she leans over him on her knees and picks him up by his jacket bringing him closer to her. She leans down and whispers to him “I know your secret….One For Allllll~. You’re weak. You won’t fight anymore. You can’t. So you have two options. Either forfeit the round…or I tell this entire stadium and the whole world about your secret.”

Izuku, having no choice, gives up. As she leaves the arena, she glances up at Toshinori and smirks. Considering that’s all she wanted, she doesn’t fight as hard in her next fight and loses.

She secretly joins the LOV and drops out of UA in order to avoid her father and Izuku. She’s done trying to get her father to love her.

Of course Izuku tells All Might of what she said to him and Toshinori starts to freak out. He tries to find her but she stays hidden with the LOV, very rarely going out.

She makes a deal with Shigiraki; she’ll deal with Izuku while he focuses on All Might. She can’t bring herself to want to kill her father herself, but she feels Indifferent if he lives or dies. She’ll gladly destroy Izuku though. After all…he’s daddy’s favourite.