#I think a small part of sae's treatment of rin is also self flagellation

[goshikiology]

rin's ego as a striker is intrinsically tied to sae- both when his goal is to become number two with sae at his side and later, when he wants to become the best solely to spite his brother. sae's dissolution of their shared dream is both an attempt to free himself from the insurmountable expectation that he will become the world's greatest striker (something he realized was impossible while he was in spain), and also an attempt to free rin's ego from his own. from the beginning of blue lock, it's been established that genius goalies and defenders and midfielders (!) can be born, whereas strikers are created different from the beginning. observant, intelligent sae knows, even as a kid, that rin has something he simply doesn't- a natural sense of the field, the ability to smell a weak spot in the defense. rin's natural talent abounds, but it takes more than just talent to become a genius striker. sae knows that rin posesses talent in spades, but his underdeveloped ego (or even lack of ego entirely) is holding him back. while it might seem misguided and cruel, sae recognizes that rin's dependence on him is restrictive, and attempts to end it. it is not enough for rin to just latch on to sae's ambitions and goals. to develop the ego of a world-class striker, he needs to develop ambition and ego of his own.