That’s why he despises Tanjiro who is considerably weaker than him at the time. Rui is the Lower Rank Five demon of the Twelve Kizuki. He is the main antagonist of the Mount Natagumo arc.

They cleverly do this by showing it through the lens of Tanjiro Kamado ... one of the Demon Slayer characters who became a villain. Rui was the Lower Moon Five demon. As a human, Rui was born ...

In the heat of battle against Rui, a lower-rank demon with threads sharp enough to slice flesh like silk, Tanjiro’s desperation awakened something ancient within him. Flames spiraled from his ...