Norman does aknowelage that his capabilities are worth of a genius, and still he has no god complex. Instead, through the series he constantly considered himself to be the most, and only, disposable person. He not once considered himself the most valuable, and, on the opposite, he believes he's the only one that should put his life on the line, or who should lose his humanity doing actions he would never let anyone else take the burden of. You see, I really enjoy how humble his character was made; I don't think there's a lot of other characters in medias that are displayed being so smart yet so modest and free from any vanity. Additionally, particularly in the further part of the series the reader is constantly reminded about how flawed he is, which makes him all the more human.

Norman knows that even though he's incomparably smart, there's still plenty of things he can learn: on the top of the list, how to be a better human being (therefore him looking up to Emma and wanting to become more like her). He's someone who realizes that wit and knowledge aren't everything, and that those qualities don't make him superior to anyone else, and I respect him for that.

Now, I know Norman has been repeatedly compared to a god after his return in the manga, by Hayato, Emma and later on by himself as well. If Hayato was surely blown away by his position, power and charisma, I believe that the latter associations were firstly ment to emphasize on how he was carrying the world's weight all by himself. Emma is begging him not to take once again all the burden on his shoulders:

On his side, Norman is talking about how he's willing to do everything in his power to save everyone:

There's not an ounce of selfishness in Norman's words. That's why, no matter how smart he is, once Emma is asked to describe him his incredible wit is not the first of his qualities that comes to her mind: Norman is extremely kind. He's good-hearted. He's compassionate and altruistic. He cares about the people he loves. He tries - often fails - but still he tries to be a better person. And I just adore how in this series he was given much deepness and complexity rather than making him just be the next one-dimentional smart guy :')

A while ago I updated this