While at the biannual Hashira meeting, all present witnesses a heavily wounded boy fall from a hole in the sky. The first one to respond to the mysterious surprise is Shinobu, the Insect Hashira. The boy is dressed in a rugged demon slayer uniform under a green checkered haori. He looks unique with his wild burgundy hair, a birthmark that peaks under the lump that swallows half his face. All the Hashira notice that he has Hanafuda earrings with the sun overlooking a mountain depicted on them1.
Shinobu attends to the boy's wounds, not knowing what is happening inside the body2. As she carefully examines him, she realizes that his injuries are not just physical but also involve a strange energy that seems to be pulsating through his veins. The other Hashira gather around, intrigued and concerned about the boy's sudden appearance and the mysterious circumstances surrounding him.
As the boy regains consciousness, he introduces himself as Tanjiro Kamado, a demon slayer from another dimension. He explains that he was in the middle of a fierce battle with a powerful demon when a portal opened up, transporting him to this world. Tanjiro's presence sparks a series of events that lead the Hashira to uncover a hidden threat that could endanger both their world and Tanjiro's.
Together, the Hashira and Tanjiro embark on a journey to find a way to send him back to his dimension while also battling the new demonic forces that have started to emerge. Along the way, they form strong bonds, learn from each other's strengths, and face numerous challenges that test their resolve and determination.