His way of making up for that lack of talent is by using Repetitive Action and consuming live demon flesh to gain their attributes. In the manga, Genya Shinazugawa would consume the flesh of the Upper Moon 4 demon to gain its attributes.
When he found out he had no talent as a swordsman, he felt mentally exhausted. His mental state pushed him into a corner. where he ended up eating a demon. Then he discovered this idiosyncrasy as his own ability.
Now Genya has taken it to the next level by cannibalizing Hantengu's flesh, consuming demon flesh so he can enhance his own demon-style powers, including regeneration.
Against Kokushibo, the strongest Upper Rank, Genya consumed his hair and a chunk of his flesh katana, gaining enough strength to develop his own Blood Demon Art which played a pivotal role in the defeat of the Upper Rank.
In the simplest terms, the reason that Genya can't use Breathing Styles stems from his inability to achieve the total concentration breathing that other demon slayers use in order to access their abilities.
Enraged by the feeling of inferiority, he slashed Yoriichi's body in half, but inadvertently broke the flute he gave him as a child. Seeing that he still thought highly of him even after his transformation, Kokushibo couldn't help but shed a tear.
For a short amount of time, he can become a demon using his bite strength and his special digestive organs." Basically, as a result of his serious gnashers and iron stomach, Genya can devour demon flesh and gain characteristics like the sharpened fangs, frosted tips, and black pupils seen in the most recent episodes.
No one killed Sanemi Shinazugawa. Sanemi almost died when he tackled his sister Genya from a window in order to protect her from a demon attack, but was saved by his friend Masachika who healed his wounds.
But since he seems mostly human -- and the fact that he can walk in the sun automatically -- dismisses the possibility of Genya having a demon body like Nezuko. The only other explanation then is that he possesses a part of it, which is also likely the reason why his regeneration isn't as efficient as true demons.
King Alexander III continues to rape Genya which allows her to poison her lips as part of The Darkling's attempted coup. After Alina escapes the Little Palace, the King falls ill due to poison. The Apparat rules in his stead until the fall of Novokribirsk.
Genya is the first of all Grisha to share her specific talent, and she is curious, knowledgeable, and kind. But she is also tool used by the Darkling to endear himself to the royal family by gifting her talents to the queen (and making her body easily accessible to the king, who sexually assaults her).
Unknowing that his mother was the demon, or "wolf", Genya screamed at Sanemi and labelled him as mother's murderer, an action that he reminisces regretfully.
Later, at the Spinning Wheel, Sergei Beznikov lets her name slip and she is found by the King and Queen. The King intends to punish her for poisoning him, but she reveals to the others that she was abused by the King for years.
He fired a bullet that not only damaged Kokushibo, but also sprouted roots that trapped him to the ground. This allowed Gyomei and Sanemi to deliver the final blow on Kokushibo, killing him soon after. Unfortunately. Genya succumbed to his injuries and his body crumbled away as Sanemi held him.
The only person who put his life on the line to save Genya was blamed and called a murderer. Such a backstory has surely traumatized the sibling duo. Genya is always angry at others because of everything he has gone through in his early life.
Genya was killed by the Upper Moon 1, Kokushibo, but not before helping the others take him down. As he was dying, his brother Sanemi regretted how strained their relationship have become, and wept as he begged the heavens to spare Genya. Like a demon, his body disintegrated as he died.
Tomioka Giyu = killed by Tanjiro Kamado. Tanjiro Kamado = killed by Nezuko kamado ( or another demon ) ; or executed for killing a hashira and have protected a demon. Nezuko Kamado = burned to sunlight , killed by a hashira , or eaten by Muzan Kibutsuji ( if she conquires the sun )
Shinobu Kocho is a capable Demon Slayer whose worthy of being the Insect Hashira. That being said, she's arguably the weakest Hashira when it comes to pure strength.
Demon Slayer season 3 episode six did more than just give us some great action, it also showed us Genya's backstory. Similar to Tanjiro, Genya's family was torn apart by tragedy. His life was destroyed after his mother was turned into a demon and had to be killed by his older brother Sanemi.
Kyogo Shinazugawa (不死川 恭梧, Shinazugawa Kyōgo) is a minor antagonist in Demon Slayer: Kimetsu no Yaiba, but an important character to Sanemi Shinazugawa and Genya Shinazugawa, being their abusive father who is partially responsible for the wrathful personalities the two siblings have.
Kyogo was married to Shizu and the two would go on to have seven children; Sanemi, Genya, Shuya, Hiroshi, Koto, Teiko, and Sumi. However, Kyogo proved to be an incredibly abusive father and husband, ruthlessly beating his family.
Furthermore, Doma is regarded as the coldest and most obnoxious demon. He frequently behaves carelessly around Muzan, which he even hates. All these aspects, as well as Doma's lack of sincerity, irresponsibility, and complete maniac-like nature, fuel Akaza's hatred for him.
It was later revealed that Akaza's desperate and stubborn pursuit of strength was to heal his sick father and to protect the ones he loved and cared about, namely his fiancée Koyuki and his teacher Keizo.