Who is Inosuke Hashibira From Demon Slayer: Complete Profile Guide- Face, Voice Actor, relationship and Release Date of Infinity Castle Arc
◆ Role in the Story (Spoilers: Mugen Train Arc and Beyond)

Inosuke Hashibira from Demon Slayer
※This section contains significant plot details from the anime and film, including the Mugen Train Arc, Entertainment District Arc, and Swordsmith Village Arc. Proceed only if you are up to date with the series.
Mugen Train Arc
In the Mugen Train Arc, Inosuke falls under Lower Rank One demon Enmu's sleep spell along with the other Demon Slayers. Inosuke's dream content deeply reflects his personality.
In Inosuke's dream, he was exploring a somewhat spacious cave with Tanjiro, Zenitsu, and Nezuko as his subordinates. This represents both his confidence that "he's the strongest" and his unconscious desire to be with his comrades.
In the battle against Enmu, Inosuke was one of those who showed the strongest resistance to the sleep technique. His wild instincts and intuitive ability to distinguish between reality and dreams were demonstrated, allowing him to wake up relatively early. In the battle alongside Rengoku, he learns the importance of teamwork and realizes that individual strength has its limits.
Entertainment District Arc
In the Entertainment District Arc, alongside Sound Hashira Tengen Uzui, he faces Upper Rank Six demons Gyutaro and Daki. In this battle, Inosuke is forced to crossdress, initially resisting but showing growth by enduring it for the mission.
In the fight against Upper Rank demons, it becomes clear that Inosuke's "Beast Breathing" has become more refined, enabling him to use multiple combination techniques. Particularly impressive was his scene where he withstood Gyutaro's poison attacks using the resistance he built up in the wild.
In this battle, Inosuke transitions from solo combat to understanding the importance of true teamwork, perfectly executing coordination with Tengen, Tanjiro, and Zenitsu. Achieving the great feat of defeating an Upper Rank demon, he simultaneously demonstrates personal growth and deepening bonds with his comrades.
Swordsmith Village Arc
In the Swordsmith Village Arc, while Inosuke wasn't directly involved in the main battles, this period is depicted as one of his continued training and growth.
Through training during this period, he achieved further development of "Beast Breathing," working on developing new techniques and improving the precision of existing ones. Particularly, his "Spatial Awareness" ability became more refined, and it becomes clear in later battles that his situational judgment in combat improved dramatically.
Source : DemonSlayer Official