Genya is a tall young man with a rough and feral appearance. He is of fair skin tone and muscular build. He has large almond-shaped eyes with dark purple irises, a large, jagged scar that ran over his right cheekbone from his ear to the bridge of his nose, and a furrowed brow, giving him a constant angered expression. He also has numerous scars across his upper body and arms. He has long, black hair in a style of a mohawk with strands framing his neck. After joining the Demon Slayer Corps, Genya’s outfit consists of a dark olive-green variation of the standard Demon Slayer uniform. This includes a button-up jacket with a stand-up collar and long sleeves, silver buttons, and a shirt pocket on the left breast, with the kanji for Destroy (滅めつ, Metsu?) engraved on the back of the uniform. A white long-sleeved collared undershirt is worn beneath the jacket, and the uniform is secured at the waist with a white belt. Over this, Genya wears his signature sleeveless, purple yukata, with the lower part of his yukata being a darker color tone. He also wears matching olive-green tattsuke-hakama pants and a pair of white jika-tabi on his feet. Genya was initially a hostile 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 Final Selection, he roughly handled Kanata Ubuyashiki by grabbing her hair and yelling at her due to his impatience, and he later provoked Tanjiro Kamado into directly confronting him with physical force as an attempt to diffuse the situation. His ill temper and brash way of speaking heavily resembles that of his older brother, Sanemi; both their behaviors mirrored that of their abusive father. However, although he was still brash, Genya mellowed with age. He became more open to cooperation during the battle against Hantengu, the Upper Rank Four, where he worked alongside Tanjiro, 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. Genya also appears to be very confident in battle, telling Aizetsu to focus on him despite the latter already having stabbed Genya with his Yari, and later announced his name to the demon and declared that he is the one who will kill him. As a child, Genya was caring and loving towards his family, looking out for them due to their father's abuse and being the second oldest of his siblings. His protective attitude stems from a promise he had made with Sanemi following their father's death, when he stated that it was now their job to be a role model for their siblings and look after their mother. He was deeply regretful of his inability to save his brothers and sisters following their mother's transformation and blamed himself heavily for his own accusation of Sanemi killing her, despite acknowledging later that he was not at fault and she transformed into an uncontrollable demon. During Sekido's near fatal attack on Genya, he shed tears of regret when he believed he was about to die without ever getting the chance to properly apologize to Sanemi for his harsh words, only encouraged to push past it when Tanjiro had rescued him and placed his faith onto him. Sanemi's refusal to acknowledge Genya made him insecure as he came to realize just how weak he is compared to his companions. When he reunited with his brother during his section of Hashira Training, he attempts to apologize and make amends with his brother, but is left demoralized when Sanemi berates him after threatening to kill him. His desire to reconnect with his brother was so strong that he confesses his habit of eating demons to fight, knowing that the practice was taboo. Nonetheless, he did whatever he could to help his allies, even if it got him horribly maimed in the process, such as shielding Tanjiro from Aizetsu's Blood Demon Art, and playing a pivotal role in the battle against Kokushibo. Despite his brother's harsh rebukes, he bore no ill will towards him, a belief reinforced by Tanjiro and eventually by Sanemi himself. As one of the five that survived Final Selection, Genya possesses a relatively strong foundation as a Demon Slayer even without utilizing a Breathing Style. His skills were exemplified in the battle against Hantengu, the fourth strongest Upper Rank, when he snuck up on two of his clones and successfully shot them both and proceeded to decapitate them in quick succession. When he consumed the flesh of Aizetsu, Genya managed to overpower the Upper Rank, stabbing Aizetsu into a tree with his own Yari and ripping off his head. When Mitsuri Kanroji, the Love Hashira, was nearly struck and killed by Zohakuten, Genya, along with Tanjiro Kamado and Nezuko Kamado, managed to save her before the attack connected. After gaining power from Zohakuten, Genya became strong enough to pick up and fling a gigantic tree without much effort, surprising the likes of Tanjiro and Nezuko, and then proceeded to throw 3 more. Genya was also capable of ripping both of Urami's arms off.