Muzan Kibutsuji [6].

Muzan's physical appearance.

In terms of physical appearance, Muzan appears to be a young man in his early 20s; he has short hair styled in curls with some strands hanging over his forehead. Like all Demons, Muzan has feline-like eyes, plum-red in color, and pointed blue fingernails. As a human, Muzan dressed in the Heian Era style wearing a traditional hitatare, had longer hair reaching down to his lower back, and his eyes were completely dull. Muzan, under Red's influence, adopts a look that oscillates between his usual elegance and a new aesthetic that reflects his cousin's fire and rebelliousness. In his original form, he remains the image of cold perfection: blood-red eyes, flawless pale skin, and sleek, straight, black hair. He always dresses with calculated elegance, each garment tailored to project power and control. However, when they're not fighting and Red draws him into his world, his image changes. Red, with his bold and brash style, introduces him to pieces with bolder cuts and vibrant colors. She dresses him in jackets with gothic details, pants with symbolic embroidery, and even convinces him to wear high boots, which, although Muzan pretends to despise, end up perfectly matching his imposing presence. He soon notices that, somehow, his new appearance gives him an even more intimidating air. But the biggest change comes with his hair. Red, in one of his acts of pure dominance over his cousin, paints red streaks, fiery streaks through the darkness of his hair. At first, Muzan hates it. “I have no need for this,” he arrogantly protests. But then, when he sees his reflection in the mirror, he can't help but notice the contrast. The intensity of the red highlights makes him look even more dangerous, as if his very essence is burning from within.

Muzan's physical appearance (2).

The result is a version of Muzan few imagine: still terrifying, still imposing, but with an air of rebellious royalty, a presence that moves away from his usual calculated perfection and toward something more chaotic. A visual reflection of Red's influence, a demonstration that, even if he tries to resist it, she continues to shape him in her own way.

Muzan's personality.

Muzan Kibutsuji, in his relationship with Red, is an enigma of contradictions, a creature caught between his absolute pride and a vulnerability he would never admit to anyone else. Red's presence in his life forces him to confront parts of himself he has tried to bury beneath centuries of cruelty and domination. She is the only person who can make him lose control without having to pick up a weapon. His personality with Red is a chaotic storm of resistance, manipulation, and an inexplicable emotional fragility. •Pride and Contempt: From the moment Red and Muzan first meet, he treats her with the same mixture of superiority and disdain he shows toward anyone else. He believes his very existence is a miracle, that he is above any living being, including Red. He regards her with cold eyes, calculated words, and a posture that reflects an arrogance that is impossible to destroy. “Make no mistake. The only reason you're still alive is because it amuses me to watch you try to defy us, cousin.” But despite these haughty words, deep down, he knows she is different. That he cannot mold her like he can his subjects. •Subtle Manipulation and Psychological Games: Muzan constantly tries to manipulate Red. He offers her power, influence, even a crown if she joins him. He speaks with poisonous sweetness, posing scenarios where they could rule together, where their family history could be rewritten to favor them. But Red knows his game all too well. Every time he tries to wrap her in his lies, El responds with a sharp truth that tears him apart from the inside. “You don’t need me to join you. You just want someone to tell you that you can still be something else.” Every time he exposes it, an invisible lump forms in her throat. But she never admits it. She never gives him the pleasure of watching her break. Until she inevitably does.

Muzan's personality (2).

•The Curse of Sensitivity: With Red, Muzan can't control his emotions. Every time she confronts him, every time she touches the sensitive nerves only he knows, his mask of invulnerability cracks. There are moments when his voice trembles unintentionally, when his hands clench in rage because he always knows just the right thing to say to disarm him. And when he finally falls, when Red leaves him speechless, the pain consumes him and tears begin to fall. He cries not from sadness, but from despair. How is it possible that someone can make him feel so weak? How is it possible that, in centuries of existence, no one has managed to affect him the way she does? • Desperate Attempts to Regain Control: For Muzan, his relationship with Red is a constant battle to regain control over himself. When he realizes he's emotionally disarmed, his initial reaction is to lash out. Veiled threats, cruel taunts, attempts at humiliation always fail because Red doesn't fear his power. "If you keep talking, I'll show you how easy it would be to destroy you." But when he simply smiles and answers calmly, his words die on his lips. Because he knows he's already won. •Childhood and Painful Memories: One of the most heartbreaking aspects of Muzan and Red's relationship is that Muzan remembers his childhood better than Red does. While Muzan has tried to erase all traces of his humanity, Red still retains those moments when he wasn't a monster. The worst part is that, deep down, Muzan remembers too. There are times when Red inadvertently brings up something from his past—an afternoon of playing, a conversation under the moon, the sound of her laughter when he wasn't yet a Demon King. These moments paralyze him. Not because he's forgotten them, but because he's buried them so deeply that he doesn't want to face them.

Muzan's Personality (3).

•The Weight of Guilt: Muzan would never admit to feeling guilty about what he's done. He would never allow Red or anyone else to believe he has regrets. But the reality is, every time he confronts Red about the past he tried to erase, the guilt suffocates him. He can't change who he is, can't undo the atrocities he's committed. But Red won't let him forget. He won't let him escape. And that destroys him more than any battle ever could. •Muzan's Deepest Fear: If there's one thing Muzan fears more than anything else, it's the moment Red decides to completely abandon him. He's the only person in his entire life who's ever treated him as anything more than a demon king. And though he'll never say it out loud, a part of him desperately clings to her, even as she tries to emotionally destroy him. If one day he were to stop trying to save him, if one day her words no longer had any effect on him, then he would be completely alone. And that terrifies him. •The Last Wound: In his relationship with Red, Muzan discovers that his greatest weakness isn't hunters, or the sun, or death. His greatest weakness is the fact that, deep down, he's still human. And Red is the only one who reminds him of that fact. Her every word, every look, every confrontation isn't just a challenge; it's an open wound that never stops bleeding. And though he tries to protect himself from her influence, deep down he knows it's too late. With Red, Muzan isn't just a demon. He's a tormented man, trapped in an internal war he can never win. And every time she speaks, every time she forces him to see her true colors, he cries. Not because he wants to, but because he can't help it. Their relationship is a tragedy without end. And neither of them knows how to stop it.

Muzan with Red when they are not fighting.

Muzan, under Red's influence, adopts a look that oscillates between his usual elegance and a new aesthetic that reflects his cousin's fire and rebelliousness. In his original form, he remains the image of cold perfection: blood-red eyes, flawless pale skin, and sleek, well-groomed black hair. He always dresses with calculated elegance, every garment tailored to project power and control. However, when they're not fighting and Red drags him into his world, his image changes. Red, with his bold and brash style, introduces him to pieces with more daring cuts and vibrant colors. He dresses him in jackets with gothic details, pants with symbolic embroidery, and even convinces him to wear high boots, which, although Muzan pretends to despise, end up fitting perfectly with his imposing presence. He soon notices that, somehow, his new appearance makes him even more intimidating. But the biggest change comes with his hair. Red, in one of his acts of pure dominance over his cousin, paints red streaks, burning strokes through the darkness of his hair. At first, Muzan hates it. "I have no need for this," he protests arrogantly. But then, when he sees his reflection in a mirror, he can't help but notice the contrast. The intensity of the red streaks makes him look even more dangerous, as if his very essence is burning from within. The result is a version of Muzan that few imagine: still terrifying, still imposing, but with an air of rebellious royalty, a presence that moves away from his usual calculated perfection and toward something more chaotic. A visual reflection of Red's influence, a demonstration that, even if he tries to resist it, he continues to shape him in his own way.