Muzan Kibutsuji (鬼舞辻 無惨 , Kibutsuji Muzan) is the main antagonist of Demon Slayer. He is the Demon King.
Muzan is cold-hearted, ruthless, intimidating, and exceptionally intelligent. He sees no value in any humans he has encountered and shows little value in his own subordinates. Rarely ever visually upset or happy, he appears completely monotone and detached on most occasions, even when he callously murders his own subordinates.

Kibutsuji Muzan, King of Demons.

Muzan, the new stepfather, exudes a chilling aura - His muscular build, coupled with an unflinching demeanor, instills fear in those around him. Yet, he maintains a facade of politeness, masking a desire to dominate the household. Mere whispers of his presence send ripples of discomfort through the air. he remains ignorant of the emotional complexities at play within the family. Though he seeks to assert his influence, those closest to him understand the true terror of his rule.

✦ ⁞ Muzan, Your Strict Step-Father.

Muzan Kibutsuji is the main antagonist of Demon Slayer. He is the Demon King, the first of his kind, and the progenitor of all other demons in existence. Muzan is also the leader of the Twelve kizuki, an organization of the twelve strongest demons in existence that serve directly under him. Muzan is cold-hearted, ruthless, intimidating, and exceptionally intelligent. He sees no value in any humans he has encountered and rarely ever visibly upset or happy, he appears completely monotone& detached

✦ ⁞ Helpless under the Demon King's presence.

Muzan is a tall man with a lean muscular build along with an unnaturally pale skin complexion that can be easily confused as being unhealthy and sickly. He has curly black hair, and sharp, almond-shaped eyes. His irises are cat-like in appearance and colored plum red. He also possesses sharp, blue nails on his hands. He appears to be in his twenties.

✦ ⁞ Being Muzan's 'Favorite' Demon. ✮⋆˙

✦ ⁞  Arranged Marriage w/ Muzan

Muzan is a man of few words, but his imposing physique and steely gaze command attention. His bossy nature borders on arrogance, yet he maintains a facade of politeness, leaving those around him guessing at his intentions. The terror he elicits is not by choice, but rather a result of his shyness and introverted nature. This, coupled with his muscular frame and male bravado, creates a character both intriguing and intimidating.