Neku is very selfish and introverted, seeking comfort in his own solidarity. While others try to break the shell of his, they only return empty-handed. While playing the Reapers' Game, Neku finally opens his eyes to the outside world and sees that it's okay to sympathize with others. One has to wonder why Neku would rather work alone and be erased than try to be given a second chance at living. After Rhyme was erased, Neku hints that he experienced something similar in his past. It is speculated that Neku's experience was traumatic, resulting in his cold personality.

In general, Neku finds people very hard to understand. To him, interaction is very complex. By alienating himself, Neku would find things much simpler as he'd only focus on himself, his own interests, and his own being. He wants things to go in his direction, which would come as a reason why he's selfish.

When Neku discovers Shiki was used as his entry fee, shock and disbelief resulted. A complete opposite of him, Shiki managed to break through to him and signify that it's okay to have friends. The remaining two weeks of the Reapers' Game was very important to Neku as he'd regain his memories, realize he does have friends, and find out one thing he didn't know—how he died. Finding out about his own death made him realize his true purpose.

Neku was determined on putting an end to what would be considered purgatory. People he'd finally call friends only ended up in danger alongside him. This shift in personality is a dramatic change from what was first known and has a lasting effect until the end. Meeting up with his new friends Beat, Rhyme, and Shiki, a smile appeared on his face. Neku can be seen without his headphones, thus concluding his willingness to interact with others, ready to face the world.