Demon Slayer's third season revolves around the most powerful opponent Tanjiro and Nezuko have yet to face: the Upper Moon 4 Demon, Hantengu. Knowing how vital the Village of the Swordsmiths is to the Slayer Corps' operation, it only made sense that Muzan would send his minions to wreak havoc and try to snuff out one of his greatest threats.
Source：https://www.cbr.com/demon-slayer-who-killed-hantengu-upper-rank-4/
