Ness is actually a clone of the netkid (aka Tobi), whose genome was copied and preserved in case anything should happen to them on their mission with Killy. Years later, the same genome was used to synthetically create a new human. He was born when Tobi was about 14-15 and they played a supporting role in his upbringing.
While they have pretty much the same lineage, Ness inherited different physical traits from Cibo, Sanakan, and Seu than his older sibling did, and he maintained a very androgynous appearance when he was young. Both siblings are the same variation of intersex, though instead of letting it run its course, Ness’ development was manually halted and he went on TRT at the end of his teen years.
Gender-wise, he has a stronger connection to masculinity than Tobi and opts for more masculine modes of expression. But he doesn’t share the same experiences as the typical human men of the time, having been raised in semi-isolation without gender playing an important role, so he feels a slight disconnect from manhood in general.
As time goes on, it’s evident that the lives of NTG holders are quite lonely. It’s rare for broader human society to accept them after finding out who they truly are, let alone allow them to trespass on their lands due to immediate suspicion. Plus the Net agents’ ability to bypass and manipulate Net technology kinda freaks them out. Ness unfortunately takes this rejection to heart, returning the rudeness of those who shun him. Even when giving the simplest explanation for his duties that he can muster, winning outsiders’ trust is difficult.
As for his name, it doesn’t have any relation to Great Sky River like “Tobi” does; I was quite literally traveling through Scotland when I learned what it meant. (tho it kinda does mean "river" lmao) At least his name kinda matches Killy’s in that they’re both of Celtic(?) origin!