Yukine

Yukine, born Haruki Tajima, is Yato's shinki: a spirit bound to serve as his blade and his guidepost, keeping the god from acting recklessly. Physically he looks like a boy of about fourteen, shorter than both Yato and Hiyori Iki, and speaks his mind bluntly, with a sharp sense of humor that makes him easy to like once people get past his prickliness.

Underneath the attitude is a strong, still-developing moral compass. Yukine works hard to correct his own mistakes and gradually takes real pride in his role guiding Yato, to the point of feeling threatened whenever the god leans on other spirits instead of him. He is quick to act on emotion, sometimes recklessly, especially when someone he cares about is in danger, and he can shut people out or lash out when he feels betrayed.

What keeps him sympathetic through all of that is the loyalty underneath — once Yukine decides someone matters to him, he protects them fiercely, even at real cost to himself.