Figure | Demon Slayer: Kimetsu no Yaiba | Muzan Kibutsuji | Banpresto Demon Series v5

Muzan Kibutsuji is the first demon and the origin to many other Demons in the anime series, Kimetsu no Yaiba or the English title Demon Slayer. He serves the series as the main antagonist being the source of all the Demons and is solely responsible for the slaughter of the Kamado family.

Demon Slayer: Kimetsu no Yaiba  (from Kimetsu no Yaiba Wiki)
Demon Slayer: Kimetsu no Yaiba (lit. "Blade of Demon Destruction") is a manga series written and illustrated by Koyoharu Gotoge. It has been serialized in Weekly Shonen Jump since February 15, 2016. The series is republished in English by Viz Media. The series officially ended on May 18, 2020 (Weekly Shonen Jump Issue #24) with a total of 205 chapters.

STORY: In Taisho-era Japan, Tanjiro Kamado is a kindhearted boy who makes a living selling charcoal. However, his peaceful life is shattered when a Demon slaughters his entire family. His little sister Nezuko is the only survivor, but she has been transformed into a Demon herself! Tanjiro sets out on a dangerous journey to find a way to return his sister to normal and destroy the Demon who ruined his life.