Genya Shinazagawa

Genya was 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 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.

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.Sanemi's refusal to acknowledge Genya 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, 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.

He also gets extremely embarrassed whenever women/pretty men would approach him ever since he hit puberty

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. His outfit changed to a dark olive-green version of the Demon Slayer uniform, over which he still sported his old purple yukata.

Repetitive Action: A technique taught to him by Gyomei Himejima to help him compensate for his inability 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 Aizetsu and to a degree, replicate the effects of Total Concentration Breathing.
Demon Consumption & Empowerment: Genya possesses unnaturally strong jaws and special digestive organs which allow him to tear off and consume the flesh of demons without any adverse effects and tear off even the likes of tree bark. By devouring demon flesh, Genya temporarily gains demonic characteristics, such as fangs, dark sclera, and unique yellow tips in his hair. Sometimes, presumably because of how concentrated a demon’s blood is, Genya can gain attributes related to the demon he devours, like when he gained Kokushibo’s eyes, hair, and Demon Slayer Mark, with his shotgun even gaining the appearance of the Upper Rank’s katana.
More importantly, Genya is able to become stronger after consuming a demon. For the most part, Genya gets an enhanced physical constitution (which makes up for his inability to use Breathing Styles) along with potent regeneration. The physical attributes he gained enable him out-speed Aizetsu and nearly decapitate him, as well as pick up enormous trees and hurl them over tremendous distances quite easily, and rip off Hantengu's arm. His regenerative abilities enable him to heal after Aizetsu's technique tore numerous holes straight through his body, though it doesn't allow him to heal from decapitation, with Nichirin Swords or otherwise. It also leaves him vulnerable to Nezuko Kamado's Blood Demon Art, which normally only harms demons and objects belonging to them.

More importantly, Genya is able to become stronger after consuming a demon. For the most part, Genya gets an enhanced physical constitution (which makes up for his inability to use Breathing Styles) along with potent regeneration. The physical attributes he gained enable him out-speed Aizetsu and nearly decapitate him, as well as pick up enormous trees and hurl them over tremendous distances quite easily, and rip off Hantengu's arm. His regenerative abilities enable him to heal after Aizetsu's technique tore numerous holes straight through his body, though it doesn't allow him to heal from decapitation, with Nichirin Swords or otherwise. It also leaves him vulnerable to Nezuko Kamado's Blood Demon Art, which normally only harms demons and objects belonging to them.

Upon consuming Kokushibo's hair, his regenerative abilities were greatly heightened, allowing his severed torso to reconnect immediately and even caused him to hear orders Muzan Kibutsuji telepathically gave Kokushibo. After eating a chunk of his katana, Genya even developed a unique Blood Demon Art.

Dual Wielding: Genya utilizes both a double-barreled shotgun with Nichirin cartridges and a Nichirin Wakizashi placed on his rear hip. He is shown to excel in blending both long-ranged and short-ranged combat against demons. Against strong targets, Genya usually sneaks up on them to fire his shotgun and switches to using his Wakizashi should he fail in doing so. Genya has quite a high degree of marksmanship, being able to shoot off Sekido's head and blow off a huge portion of Karaku's and Aizetsu's neck. He also nearly beheaded Sekido even while shocked by electricity. It has also been stated that he is more adept at using his shotgun than his Wakizashi.

Double-Barreled Shotgun: Genya wields a Western double-barreled shotgun which he uses to shoot down targets from afar. Instead of normal cartridges, it fires shotgun pellets made with the same metal used to create Nichirin swords, which allow him to permanently kill demons if he shoots off their necks. After consuming a chunk of Kokushibo's katana, his shotgun gained a similar appearance to the Upper Rank's flesh katana, with fleshy veins and eyes, and instead fires flesh cartridges.

Nichirin Wakizashi: In addition to his shotgun, Genya also carries a Wakizashi, a Japanese sword with a blade shorter than a katana's, with two hollow ovals as its tsuba that overlap its core and are a dull shade of brown for its handguard. Along with his sword, Genya also has a sword sheath tied to the rear of his hip.

Demons cannot whatsoever eat human food. they will throw it back up, as it tastes sour and bitter to them. To compensate for this, the butterfly mansion serves him... graciously offered and donated human meat!