Neku is fundamentally a loner—detached, introspective, and openly apathetic about the world around him. When forced into the game, he's genuinely antisocial, the kind of person who'd rather be alone than deal with other people. He doesn't trust easily and has zero interest in helping anyone but himself. Music and graffiti art are basically his only outlets, and they matter way more to him than people do.
Things get complicated when he wakes up in Shibuya with no memory of how he got there. He has amnesia, can't remember anything, and has to piece together what happened to him as the days go on. His memories gradually come back to him, but it's a slow process—one day at a time.
Content compiled by AnimeList.moe from publicly available sources.