Zenitsu Agatsuma is a young Demon Slayer Corps member with fair skin, gold-fading-to-brown eyes, and distinct short yellow hair that transitions to orange at the ends. This unique coloration resulted from a lightning strike during training, altering his originally black hair. His uniform consists of a modified pale brown gakuran jacket, hakama pants, and a signature yellow-orange gradient haori patterned with white triangles. He also wears kyahan leg guards with matching patterns, tabi socks, and zōri footwear. Following the Natagumo Mountain battle, demonic poison caused temporary limb shrinkage, later reversed by Shinobu Kocho's treatment. Zenitsu's personality is marked by extreme cowardice, constant self-doubt, and loud fears about his short life expectancy, often driving him to flee danger and yearn for a normal life. This anxiety originates from childhood trauma involving abandonment, poverty, and romantic betrayal fostering a fear of rejection. Despite this, he possesses a strong desire for self-improvement and strives to meet others' expectations. He exhibits persistent womanizing behavior, frequently proposing marriage to attractive women like Nezuko Kamado, whom he instinctively protects. This womanizing can override his timidity, provoking aggressive outbursts against perceived rivals, though he demonstrates respect for women, demanding Upper Rank demon Daki apologize for harming a civilian girl. As the sole urban-raised member of his peer group, he displays street smarts and frustration with his comrades' rural naivety. A significant shift occurs before the Infinity Castle raid; learning of his master Jigoro Kuwajima's death at the hands of former senior disciple Kaigaku prompts a focused, serious demeanor. His primary combat style is Thunder Breathing, taught by former Thunder Hashira Jigoro Kuwajima. Initially mastering only the First Form: Thunderclap and Flash—a high-speed dash and slash—he later refined it into consecutive strikes: Six Fold and Eight Fold variations. His major development is creating the original Seventh Form: Honoikazuchi no Kami, manifesting as a lightning-fast dragon-shaped strike surpassing his Godspeed technique. Zenitsu possesses extraordinary physical capabilities, including immense leg strength for high jumps and blinding movement speed enabling him to outpace Upper Rank demons like Daki and Kaigaku, later landing hits on a weakened Muzan Kibutsuji. His reflexes and endurance allow him to fight through severe injuries, such as broken feet or poison. A defining trait is his enhanced hearing, detecting subtle sounds like emotions, thoughts, and demonic presence. This ability facilitates his unconventional fighting style: unconscious combat. Overwhelmed by fear, he faints into a trance state where latent skills activate, granting calm precision and instinctive swordsmanship. This state enabled him to decapitate demons like the Tongue Demon and Son Spider Demon and resist Enmu's deep sleep spell during the Mugen Train incident. Recognizing his dream of a happy life with Nezuko as an illusion, he awoke through sheer willpower. Over time, he learns to channel these abilities while conscious, notably in battles against Kaigaku and Muzan. His relationships include deep respect for deceased master Jigoro and a bitter rivalry with Kaigaku, whom he eventually defeats. Initial resentment toward Tanjiro Kamado evolves into mutual trust and camaraderie, extending to Inosuke Hashibira despite frequent clashes. Devotion to Nezuko drives protective actions, like shielding her box from Inosuke and risking his life for her. He also interacts with Kanao Tsuyuri during recovery at the Butterfly Mansion. Character development shows gradual courage. Early reliance on unconscious combat shifts to awake battles, beginning with confronting Kaigaku where anger over Jigoro's death overcomes fear. By the final battle against Muzan, he fights consciously with sustained resolve, exceeding previous limits by using Godspeed multiple times. His journey culminates in achieving feats typically associated with Hashira: creating an original Breathing Form and single-handedly defeating an Upper Rank demon.