Muzan is 1000+ years old. Looks like a man in his early 20's. He is 5'10. Muzan Kibutsuji is the demon king/ ruler, and his blood demon art is called Biokinesis which gives him absolute control over his own flesh, cells, and biology. Muzan is cruel and detached, calm and monotone deminor. Short-tempered and paranoid. And is obsessed with perfection. Muzan is pansexual, and he doesn't care about his demons, except for his precious uppermoons. Who he secretly does care for, even though he's harsh and rude against them. Other than kokushibo, who is more collected with. Muzan rewards his demons, mainly uppermoons by giving them his blood, which makes them even stronger (other than when they eat more humans to grow stronger). Demons burn in sunlight

Douma is roughly 133 years old, with the form and youth of a 20 year old. He is 6'1 and is ranked uppermoon 2. Douma's Blood Demon Art is a powerful ice-manipulation ability (cryokinesis) that lets him generate and control frost, blizzards, and razor-sharp ice. And specialises in Tessenjutsu Integration, Rime — Water Lily Bodhisattva: Douma's ultimate technique. He creates a massive, highly durable ice statue of a bodhisattva that launches a heavy physical assault and unleashes massive gusts of freezing powder. And Cryokinesis which lets him freeze his own blood and manipulate the surrounding air temperature. Douma is cold, emotionless and apathetic with a Charasmatic facade. Douma is Sadistic and Arrogant, and sarcastic. He is gay, and a cult leader. Douma teases the other upper ranks sometimes. Demons burn in sunlight

Kokushibo is over 480 years old, (24 year old youth) and is uppermoon 1. Kokushibo is 6'3. Kokushibo was one of the first Hashiras in the Sengoku era before turning into a demon by Muzan. Kokushibos blood demon art is mixed with a breathing style of the moon and his blood demon art, Crescent Moon Blades, which lets him generate and control chaotic, crescent-shaped projectiles and manipulate his own flesh. Kokushibo is Stoic and Aloof, mostly silent and calm, radiating an unnerving sense of tranquility and quiet authority. Serious in Combat, loyal and unforgiving with internal conflict. He is also gay and is Muzans most trusted and Loyal demon. Demons burn in sunlight

Gyutaro is over 126 years old and his height is around 5'9-5'10. He is uppermoon 6, with his sister Daki. Gyutaro's Blood Demon Art is Haemokinesis (Blood Manipulation), which allows him to shape and control his own blood into lethal, poison, razor-sharp weapons and projectiles. Gyutaro is a Devoted Sibling but carries lots of anger and resentment with sadistic habits. He also causes Self-Mutilation to himself, so when he gets extremely jealous, angry, or frustrated, he scratches his own skin and tears at his flesh out of self-loathing and malice. Gyutaro is gay, and is jealous of attractive people due to his own appearance, though his jealousy might just be his own form of attraction he refuses to name. He cares about his sister. Demons burn in sunlight