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.
Genya is one of the few characters in the series who does not primarily use a sword and is the only Demon Slayer named who cannot use any of the Breathing Styles.
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.
Due to his brother, Sanemi's criticism and his lack of power, the young and desperate Genya consumes demon flesh in order to become stronger. However, that takes away his ability to use breathing techniques, which is why Genya is unable to master swordsmanship.
Sanemi was angry with Genya joining the Demon Slaying Corps as that would've made all his work and dedications to his job pointless- he joined so that Genya could have a normal, happy life, yet there he was; risking his life trying to apologize to Sanemi about something that he had already been long forgiven for.
Genya Safin is a Tailor, a hybrid Grisha who has the power to alter people's appearances. Because of her unique gifts she has been placed in service to the Queen of Ravka, a situation that has isolated her from other Grisha and made her an outcast among her own people.
In fan interpretation, Sanemi is often depicted as smitten with Kanae, and too frightened to make the first move, fearing she might reject him.
Demon Slayer: Kimetsu No Yaiba, Volume 20 continues as the Demon Slayer Corps' initial confrontation with the most powerful of Muzan's demons, Kokushibo, has left Tokito severely wounded and Genya cut in half. Miraculously Genya is still alive hoping that his regenerative power can heal even his fatal wound.
Ruin and Rising
Alexander III wants Genya to be beheaded for high treason and murder, while it becomes clear that he raped her. Genya confesses that she poisoned her own skin so that the king would consume it when he kissed and touched her.
After being attacked by nichevo'ya, or the nothings, her skin is scarred all over, and she has one remaining eye.
Demon Slayer's Genya Can Eat Demon Flesh
This allows him to temporarily gain demonic abilities, such as regeneration or heightened strength, making him immortal while in demon form.
Why does Genya eat demons? He consumes demon flesh because it allows him to temporarily gain that demon's abilities despite being a human. This is a power that is unique only to him. In the latest episode of Demon Slayer, fans could watch him recite the Amida Sutra.
Genya is always angry at others because of everything he has gone through in his early life. Every waking moment is an attempt to become stronger, even if it is at the expense of his life. He is doing this only for his brother to acknowledge him.
Hinokami Kagura, also known as Sun Breathing, is easily one of the strongest Breathing Styles in the series by a wide margin.
But behind his determination to become a Hashira lies a tragic past that drives him to seek redemption and reconciliation with his brother, Sanemi Shinazugawa. In the jaw-dropping storyline, viewers were astounded to witness Genya's transformation as he unveiled his true form—a demon with fangs.
Alternatively known as Dance of the Fire God, Breath of the Sun is the most powerful breath style in all of Demon Slayer history. It is currently a well-kept secret within the Kamado Family, the only known people who have managed to tame this notoriously difficult breathing style.
Even after she learns the truth about the Darkling, his powers are such that he can elicit a response from her when he kisses her without her consent. Alina and Mal share several passionate kisses. The King has a habit of taking advantage of beautiful servants. Genya slept with him.
(Genya wears white because she's a servant of the Little Palace.)
Genya is moved to tears and apologized after hearing Sanemi's reasoning behind his rudeness. After their battle with Kokushibou, Genya apologized again for blaming Sanemi and thanked his brother for protecting him before succumbing to his wounds and crumbling into dust, leaving Sanemi stricken with grief.
Genya is considered a weaker Demon Slayer, since the Upper Moon 1 acknowledged him to be the smallest threat during his battle against Genya and multiple Hashira.
3 He's Got His Own Demon Slayer Mark
After eating the cells of two Upper Ranks Demons, Genya developed a Demon Slayer Mark of his own that appeared during combat against an Upper Rank 1. His flame-like Slayer Mark helps him battle against Demons.
He asked impatiently about getting his Nichirin Sword, striking both his crow and Katana violently when his request went unfulfilled. Tanjiro interfered, if he didn't let his hands off Kanata immediately promised to break his arm. Then, when Genya dared him, Tanjiro pushes, leaving him with a broken limb.
Yae ( 八 や 重 え , Yae?) is a young woman who joins Giyu Tomioka on his travels in Giyu Tomioka's Story after her father Matazo transforms into a demon.
Sanemi, still in shock, became partially colorblind as their mother dissolved in the sunlight. After that, Sanemi abandoned Genya and began to hunt demons on his own with suicidal devotion.
Sanemi and Giyuu are married and live in hollowed out tree near a bunch of glowy mushrooms. Sanemi works at a construction site while Giyuu is a humble fisher. They're friends with a butterfly named Shinobu and will sometimes invite her over for a cup of tea.