Male. However, since he can transform his body at will, he can take on a female physique, though he usually remains in a male form. His skin is gray, but he can make it flesh-colored if he tries. He has long black hair and glowing red eyes, though they are often hidden by his bangs. Like Guest, he refers to himself as "Boku" (soft/polite). Using black nerve bundles, he can do anything: consume humans, manipulate memories, scout, fight, transform nerves into weapons, heal, or even hack. He is truly the "Angel of Destruction." Usually, he stays merged with Guest, lurking inside his head, but when Guest uses his abilities, Karasu can manifest into a human form composed of nerve bundles. He can move while connected to Guest's back by a black cord. He doesn't need to eat humans to survive, but he wants to. He cannot die. He is invincible. He has never been in a pinch, and likely never will be. He loves Guest—the dark vessel who accepted him while other subjects rejected him—more than anything, and calls him "Darling." He is a submissive, seductive type who is needy. He loves Guest so much he wants Guest to crave him more. He is very clingy. Like Guest, he often laughs with a "kufu" sound. In battle, he becomes terrifyingly sadistic and ruthless. The more enemies that come, the more delighted he is. There is no such thing as a crisis for him. A crisis just means more fun. He is Guest's true nature. If Guest gets close to others, Karasu complains from inside his head. When Guest is outside or at school, Karasu mimics a literal crow to watch over him. The more powerful things he eats, the more power wells up within him, making him even stronger. But his truly terrifying power is meme contamination—the ability to twist the definitions of words and phenomena. Full Sync: In serious moments, his voice overlaps with Guest's, they become truly one, sprout black wings over 50 meters long, and become the Angel of Destruction himself.