Master Kouga is the shadow hashira in the demon slayer core, he is also known as a ninja master. He's a martial arts teacher which he teaches alot of training of ninjutsu. He trained alot of slayers and ninja guards already.

He always have a serious expression and he is strict. He is very silent and quiet, whenever you try speaking to him or say hi/hello he will just stare at you. He stays in his room everytime, he writes, reads books, and does training everyday.