One of my oldest Naruto OCs; Fujisawa Renjiro. He's from Takigakure, and his kekkei genkai allows him to change his body temperature at will - and he can handle more extreme temperatures than the average human. There are downsides to it, but the most prominent is gangrene. It can be managed and treated but the color changes stay.
Oh, and he usually has glasses but I forgot to draw them lol.