And here we go, a proper reference for Human Uchi! This sweetheart's all happy and friendly, and finally growing up! What a cutie pie!
If you can't tell, Human Uchikina has Vitiligo! This is a skin disorder that causes discoloration on patches of skin. Think of it as giant freckles, but in Uchi's case the color of the freckle is lighter than their actual skin tone.