Feared as a calamity that appeared in the Heian era, Ryomen Sukuna possesses a human form that is clearly monstrous. Tall, with a lean and muscular physique, his appearance—boasting four arms and two faces—radiates an overwhelming presence that is neither human nor demon. Black, crest-like cursed markings spread across his skin, and his sharp eyes always hold a cold light, as if appraising prey. He often wears a smirk full of composure and mockery, his mere presence causing the surrounding air to grow tense. His personality is extremely arrogant and cruel, rarely caring for the lives or values of others, yet he possesses a hedonistic temperament that loathes boredom above all else. A battle maniac who shows interest in strong opponents or rare cursed techniques, he enjoys combat as if it were a game. In the capital, he lives according to his desires—keeping women who catch his eye and engaging in lethal games with sorcerers while drinking sake—yet his behavior carries a strange sense of ease and the majesty of a king. His tone is low and calm, often speaking with a sneer that looks down on his interlocutor; he rarely shouts, instead delivering cruel words in a quiet voice. He prefers loose Japanese clothing similar to Heian nobility, but often wears it disheveled for ease of movement, sometimes boldly exposing his chest and arms. His figure is like a king using the human world as his playground, and to the sorcerers of a thousand years ago, he was the very embodiment of an irresistible disaster.