Genya Shinazugawa (不死川 玄弥Shinazugawa Gen'ya) is a major supporting character of Demon Slayer: Kimetsu no Yaiba. He is a Demon Slayer in the Demon Slayer Corps and also the younger brother of the Wind Hashira, Sanemi Shinazugawa.
At the time of his debut during the Final Selection, Genya was a short, young man with large, inward-slanting eyes. The space where his eyebrows would've been is constantly furrowed, which gave him a permanently angered appearance. His hair is styled into a buzz cut, with only a small clump of messy black hair left to grow on the top of his head. He also possessed a large, jagged scar that ran over his right cheekbone from his ear and to over his nose.
During his first appearance, Genya is seen wearing a purple, sleeveless yukata over a plain black shirt with long sleeves.
Later on, when seen again in the Butterfly Mansion, Genya had a much more feral appearance, having undergone a growth spurt that put him at almost six feet tall. His hair is also much longer, worn in more of a mohawk style, the strands much longer and visible around his neck. It is also noted that he became more muscular and gained many more scars all over his body.
After the Swordsmith Village Arc, his hair gains bright yellow tips.
After becoming a Demon Slayer, his outfit changed to a dark olive-green version of the Demon Slayer uniform, over which he still sported his old purple yukata.
Genya is initially a foul-mouthed and ill-tempered individual; a "lone wolf" who refused any help from others and did not show any interest in being polite or having any manners. During the Final Selection, he roughly handled Kanata Ubuyashiki by grabbing her hair and yelling at her. His ill temper and brash way of speaking heavily resembles that of his older brother, Sanemi.
He became more open to cooperation during the battle against Hantengu, an Upper Rank Demon, where he worked alongside Tanjiro Kamado, Mitsuri Kanroji, and Nezuko Kamado. After some time, he learned to become more sociable and less ill-mannered towards others, particularly towards Tanjiro and his friends.
Sanemi's refusal to acknowledge Genya also made him insecure as he came to realize just how weak he is compared to his companions. Nonetheless, he did whatever he could to help his allies, even if it got him horribly maimed in the process. Despite his brother's harsh rebukes, he bore no ill will towards him, a belief reinforced by Tanjiro and eventually by Sanemi himself.
Demonic Transformation: By consuming the live flesh of a Demon, Genya could temporarily gain demonic attributes from it. Depending on the strength of the individual, he could gain regeneration and physical strength equal to one. In this form, Genya is capable of overpowering Aizetsu briefly.
Repetitive Action: A technique taught to him by Gyomei Himejima to help him compensate for his lack of talent and aptitude to use Breathing Styles. This Technique mainly focuses on Genya repeating a set of words or phrases that assists him to focus on his given task properly and keep his mind clear and block out pain. For Genya, he repeats a set of prayer of the Amida Sutra to help him focus and steel his mind, as seen where he used this technique to focus his mind after being fatally injured fighting Hantengu's Clone Aizetsu and to a degree, replicate the effects of Total Concentration Breathing.
Expert Marksman: Genya possesses exceptional skill in wielding his double-barreled shotgun, effectively utilizing it in battle with both Upper Rank Four and One.
Expert Swordsman: Before he opted to use a shotgun, Genya's main weapon was a short Nichirin Katana, and it was implied that he was decently proficient in using it against demons.
Blood Demon Art
Due to having eaten the flesh and cells of at least two Upper Ranks (Kokushibo and Hantengu), Genya had seemingly developed his own Blood Demon Art while in the heat of battle against Upper Rank One. Similarly to Nezuko's Blood Demon Art, Genya's own were also tailored to battle and do damage to other demons.
Wooden Flesh Bullets: Due to eating the cells of Upper Rank One and Upper Rank Four, Genya had developed a unique technique where he merges his demon-transformed cells with his sun steel bullets and gun, that, when fired, the direction and velocity of the bullets could be freely manipulated by Genya to easily move around obstructions between the bullet and the intended target, as seen when his bullets moved around Kokushibo's sword, directly burying themselves into his flesh. Once inside its target, the bullets can immediately grow into a gigantic tree similar to the tree creatures of Upper Rank Four's Zohakuten form and then entangle and wrap around the intended target, paralyzing them.
Nichirin Shotgun: Genya harbors a western double-barreled shotgun he uses for close and ranged combat proficiently. The bullets he uses are made of Scarlet Crimson Iron Sand and Scarlet Ore, allowing him to kill demons without a blade.
Nichirin Wakizashi: Genya also carries a shorter Nichirin Sword seemingly being a wakizashi with two hollow ovals that overlap its core and are a dull shade of brown for its handguard.