WARNING: The following contains spoilers for My Hero Academia Season 5, Episode 15, "One Thing at a Time," now streaming on Funimation, Hulu, and Crunchyroll.
The relationship between the Number One Hero, Endeavor, and his son, Shoto Todoroki, continues to be one of the more compelling character dynamics in My Hero Academia. The balance of power in their relationship has shifted dramatically, as Shoto is now in complete control of how things play out from here. Refusing to accept any nepotism, Shoto coldly informs his father that he is here to use him, nothing more.
In Season 5, Episode 15, Shoto woke up and chose violence, shamelessly airing their family drama in front of everyone in Endeavor's agency. Just shy of berating him, Shoto makes it clear who possesses the power now in this relationship, as Endeavor is unable to do anything when Shoto openly disrespects him in front of his sidekicks. Shoto even twists the knife a bit, reminding his father that his true hero is still the man that Endeavor replaced as Number One only by default.
Endeavor believed that Shoto was finally coming around by choosing to do his work-study under him and was clearly disappointed to hear that that was not the case. However, Endeavor shrugs it off, fully committing to what Shoto has asked of him. Though he wants to love his son properly, he seems to understand that the damage he's caused may be irreparable. When Shoto demands to be treated no differently than his friends, Endeavor complies without question. He seems to believe that if this is how Shoto wants to be treated, it must be the best way to earn his forgiveness.
Just because Endeavor wants to redeem himself doesn’t mean Shoto is going to make it easy for him. Endeavor seems to understand that he is not entitled to, nor does he deserve, anything more than whatever Shoto is willing to give. If they ever heal their relationship, it is going to be on Shoto's terms. A small part of what Shoto says to Endeavor comes off as his own defense mechanism, preparing himself for his father to disappoint him once again.
Even though Endeavor recognizes that Shoto has grown, he seems unaware that it was only possible once Shoto escaped his father's influence. In a speech that's actually kind of heartbreaking, Shoto implies that if they remove the emotion, cruelty and family drama, what's left is a father teaching his son what is best for him. Shoto has a unique and powerful Quirk that is in his best interest to master, and had his father been nurturing in his training, they would still be where they are now, except with a loving relationship.
Shoto understands that his coming to Endeavor's agency for his work-study is, in essence, his acceptance of what Endeavor was trying to get him to understand as a child. So, in order to make sure Endeavor, who also realizes this, doesn’t backslide in his treatment of Shoto, the aspiring hero makes clear that he is there of his own free will, following his own dreams. What Endeavor did to his son was wrong, unforgivably so, but now Shoto has come to terms with the necessity of the core of the lesson, that he must master his flaming half's abilities. Sure, Shoto telling his father he's using him is a little petty, but it's no more than Endeavor deserves.