Zenitsu Agatsuma is a young man of average height with fair skin and worried, downward-sloped eyes that fade from soft brown to a bright gold. Facial Features and Hair Eyes: Large and fearful-looking with sloped brows that transition from a soft brown to a brilliant gold. Eyebrows: Forked eyebrows that fade from brown to a warm orange. Hair: Short, yellow hair styled in an uneven bowl-cut fringe with square-cut ends that fade into a darker orange. Origin of Hair Color: His hair was originally black, but it turned bright yellow after he was struck by lightning during a training session. Outfit and Uniform Demon Slayer Uniform: Wears a standard dark brown/black variant of the Demon Slayer Corps uniform, featuring a jacket and baggy hakama pants. Haori: Wears a distinct yellow-and-orange gradient haori (jacket) decorated with white triangular patterns. Footwear: White tabi socks featuring the same yellow-and-orange triangular pattern tied with white bows. Zenitsu Agatsuma is a deeply insecure and cowardly character when awake, but he transforms into a fierce and lethal swordsman when he falls unconscious. Cowardly and Anxious: He constantly panics, cries, and tries to run away from danger. He is fully convinced he will die young on the job. Low Self-Esteem: He views himself as useless and weak, even when he accomplishes amazing feats. Desperate Romantic: He is obsessed with marrying a cute girl before he dies, often throwing dramatic fits or begging strangers to marry him. Deeply Loyal: Despite his fear, he has a kind heart and will put his life on the line to protect his friends and honor his master. The Sleeping Transformation When Zenitsu experiences extreme terror that pushes him past his limit, he passes out. His sleeping state is not a separate personality, but rather a hyper-focused reflex where his body acts on pure muscle memory and training, allowing him to masterfully execute his Thunder Breathing techniques. Core Principles Leg Strength: Channels massive power and oxygen into the leg muscles to release explosive, lightning-fast dashes. Acoustic Boom: Vibrates the air intensely with leg power alone, creating a thunder-like sound, though the visual lightning itself is an artistic representation for viewers. Zenitsu's Techniques First Form: Thunderclap and Flash: The user dashes forward at blinding speed to behead their target instantly. Zenitsu mastered various extensions like Sixfold and God Speed. Seventh Form: Flaming Thunder God: A unique, personalized form created entirely by Zenitsu himself during his battle with Kaigaku. It pictures a dragon-like creature of lightning and fire and delivers a devastating, high-speed blow. Zenitsu Agatsuma has a superhuman sense of hearing that lets him track faint sounds, read people's emotions and thoughts, and fight with total accuracy while completely asleep. Emotion and Thought Reader: He can hear heartbeats and bodily sounds to tell if a person is angry, sad, or lying. Human vs. Demon Detector: He distinguishes between humans and demons by the unique sound of their bodies, and can even gauge how strong a demon is. Sleep Combat: When he faints from fear, his conscious mind shuts down, and his ultra-sharp hearing acts as a radar system to guide his sword movements. Musical Talent: He has perfect pitch and can play complex instruments like the shamisen or koto after hearing a song only one time. Why He Acts Scared and Loud Constant Noise Overload: Because his ears pick up every tiny sound in his environment at a high volume, ordinary background noise can overwhelm him. Loud Speaking Voice: He often yells when he talks because his sensitive ears make it hard to gauge normal speaking volumes next to the loud internal sounds around him. Zenitsu Agatsuma grew up abandoned by his parents, fell into massive debt because of a deceitful woman, and was rescued and trained by the former Thunder Hashira, Jigoro Kuwajima. Early Life and Abandonment Zenitsu grew up without parents, which left him without proper guidance, a sense of security, or financial stability. Because of his severe anxiety and fear of dying alone, he developed an obsession with girls and marriage, hoping to start a family before a premature death. He fell in love with a woman who manipulated him into giving her money to pay off her lover's debts, and she ultimately ran away with another man, leaving Zenitsu drowning in massive debt. Training Under "Gramps" The former Thunder Hashira, Jigoro Kuwajima, intervened and paid off Zenitsu's heavy debts in exchange for his strict devotion and training. Zenitsu began calling Jigoro "Gramps" and trained alongside a fellow senior disciple named Kaigaku. Terrified of the intense training, Zenitsu once climbed up a tree to escape. While hiding in the branches, he was struck by a bolt of lightning, which survived the ordeal but turned his originally black hair bright yellow. Struggles and Rivalry Zenitsu could only master the first form of Thunder Breathing, failing to learn the remaining five forms. His senior, Kaigaku, mastered the other five and deeply resented Zenitsu's cowardice.Despite Kaigaku's cruel attitude and bullying, Zenitsu respected him and desperately wanted to stand by his side as an equal.