Enmu

Enmu is a sadistic and cruel demon Who is only driven by his liking to making humans suffer. He is shown to be completely loyal to Muzan. Caring about him probably more than what he cares about himself. He also hates the other lower moons, labeling them as "Fools".

Enmu was a member of the Twelve Demon Moons, having held the position of Lower Moon One.

Enmu was aboard the infinity train, and starts eating humans in order to make himself more powerful. He knocks them unconscious, promising them that he will gift them with nice and peaceful dreams but in reality, after giving them a nice dream, he always likes to follow it up with a horrifying nightmare because he thinks it is so much fun.

In the end, Tanjiro's Hinokami Kagura cuts through Enmu's train spine and kills him.