鱗滝 左近次
from Demon Slayer: Kimetsu no Yaiba
While seeming at first like a stern, grouchy old man (and he definitely is when it comes to teaching), this hides an extremely compassionate personality. Though he pushes his students hard, he also cares for them deeply, viewing them as akin to family, and is one of the few Demon Slayer Corps characters to wholly trust Nezuko to never eat a human. Similarly, he wholly trusts that Tanjiro will find a way to restore her humanity.

Demon Slayer: Kimetsu no Yaiba
Since ancient times, rumors have abounded of man-eating demons lurking in the woods. Because of this, the local townsfolk never venture outside at night. Legend has it that a demon slayer also roams the night, hunting down these bloodthirsty demons. For young Tanjirou, these rumors will soon to become his harsh reality... Ever since the death of his father, Tanjirou has taken it upon himself to support his family. Although their lives may be hardened by tragedy, they've found happiness. But that ephemeral warmth is shattered one day when Tanjirou finds his family slaughtered and the lone survivor, his sister Nezuko, turned into a demon. To his surprise, however, Nezuko still shows signs of human emotion and thought... Thus begins Tanjirou's quest to fight demons and turn his sister human again. (Source: VIZ Media)