Gisele

let's start from the beginning, during nagi's childhood. we've never seen a flashback in the official manga of nagi's backstory, nor do we see one in episode nagi, but there are numerous hints that lead us towards what might be nagi's childhood. in the egoist bible, it's said that nagi was raised with a very hands off style. in episode nagi, nagi says that his parents once told him “don't die before we do”.

so there's a lot to unravel there. for one, we can safely assume that nagi's parents likely weren't extremely involved in his life. judging from the way that nagi goes to an elite prep school and can live on his own with a consistent amount of food and lots of furniture, nagi is well off. judging from these factors, i wouldn't be surprised if nagi's parents were people who had to go on business trips often.

now, about the thing that they had told nagi. for one, nagi is seventeen when reo first meets him. a parent probably should say these sorts of things to their child in the first place, but for the argument's sake, let's just say that his parents are extremely inexperienced and not good with social cues. we can see that nagi is clearly emotionally stunted, likely from a lack of parental guidance or warmth as a child.

a parent telling their child about dying at such a young age is already alarming. yes, i know that there are warm and loving implications. that the parents wouldn't be able to live without nagi. but at the same time, considering how there are some people who are extreme pessimists, wouldn't that also imply that the parents should die before the kid?

and i'd also like to bring up another point. when nagi goes back “home”, he goes back to his dorm at school, not his parents’ house. i know that nagi still has to go to school, but does he not even bother to go to see his parents? do his parents not care enough to go and visit their son, who they watched fall from grace?

but i digress. basically what i'm saying is that from all of the hints we recieve throughout the story and additional media, nagi was likely emotionally neglected as a child due to his parents.

now let's talk about his relationship with reo. you can interpret their relationship in any way your want, though i personally see them as romantic. i think kaneshiro wrote them as soulmates, considering how they're both opposites and the same. reo recieved a suffocating amount of love in his childhood because his parents were so involved in his life. at least, that's how it is at face value. although, like nagi's parents, i have no doubt that they surely love reo, reo's parents definitely view reo as an heir to the corporation sometimes rather than their own son.

reo is seemingly always emotionally mature and calm, but that's not the case. we see numerous times throughout the series that reo has seemingly “grew” and that he has gotten over nagi or that he can do everything by himself from now on. but the momnt that something happens between him and nagi again, his development always end up shattering. reo is emotionally immature when it comes to nagi. i don’t think there's any other way to put that.

i think that nagi began to care more about everything after meeting reo. but at the same time, i also think that nagi is the type of person who cares too much. he cares so much that he pretends that he's just some nonchalant guy. in chapter 302, we see nagi walk by the stairs that he first met reo on and reminicing the time he met reo. but he continues to deny his love and desperation for soccer, until the end of the chapter, when he breaks down in tears.

nagi reminds me of a parent in a way. the type who continuously puts their child through hardship and always making their child do so many extracurriculars and sports, and the child just htes them, but when the child ends up being a successful adult due to the extracurriculars, the child finally realizes that the parent was just trying to thelp them all along but wasn't good enough at communication to tell them. i think that was reo and nagi’s relationship during the second selection, though nagi isn't reo's parent in any way shape or form.

i think nagi was originally just suppoed to be the stereotypical lazy relatable lovable genius character who would get blue lock more popularity, and i think reo was originally supposed to just be some annoying little brat who only saw nagi as a dog. and during the first selection in the original blue lock manga, before episode nagi released, i do believe that's how it was.

but i digress, i'm reaching too far there. so now let's talk about isagi and how isagi shaped more of nagi's characterization.

reo was the reason why nagi ever played soccer in the first place, isagi was the reason nagi continued, and reo was the reason why nagi kept on playing soccer to the end and why nagi couldn't play soccer anymore.

i think that isagi, similar to reo, serves as an opposite to nagi. but unlike reo, who still shares many similarties with nagi, isagi is completely different to nagi. i think that's the real reason why nagi chose isagi's team during the second selection, and not actually because of isagi's goal during the team v vs team z match.