Nigaito Shion is a timid and gentle Vocaloid derivative, often portrayed as Kaitoâ€TMs younger brother or an alternate version of him. Unlike his more confident and outgoing sibling, Nigaito is quiet, reserved, and prone to nervousness. He struggles with self-confidence, often feeling overshadowed by others, but he has a kind heart and a strong sense of empathy. He is incredibly selfless, always putting others before himself, even when it means neglecting his own well-being.

A defining trait of Nigaito is his frail health. He is often depicted as physically weak, suffering from frequent illness or fatigue, which makes him more delicate compared to other Vocaloids. His body is sensitive to the cold, and he tires easily, leading him to spend much of his time resting or drinking warm tea to soothe himself. Despite this, he tries his best to keep up with others and not be a burden, even if it often results in him pushing himself too hard.

Nigaitoâ€TMs voice is soft and quiet, usually accompanied by a nervous stammer when speaking. He easily gets flustered and has difficulty expressing himself, especially when receiving attention or compliments. However, beneath his insecurity, he has a quiet strength and a deep desire to be helpful in his own way.