Just as the group celebrates their survival, the atmosphere shifts. , Upper Moon Three, descends from the shadows. He represents a tier of power far beyond anything the young slayers have ever witnessed.

The mission is a trap set by , the Lower One of the Twelve Kizuki. Using his blood demon art, Enmu fuses his body with the train itself, lulling every passenger into a deep, supernatural slumber.

In the Taisho-era mountains of Japan, a massive iron beast known as the has become a tomb on wheels. Over forty passengers have vanished into thin air, and several elite slayers sent to investigate have gone silent.

Once awake, the slayers realize the train is no longer a vehicle, but a living organism of flesh and bone. While Zenitsu and Nezuko protect the 200 passengers from sprouting tentacles, Tanjiro and Inosuke climb to the engine room. With a combined strike—Tanjiro’s and Inosuke’s Beast Breathing —they sever Enmu’s neck, which has been fused into the train's chassis, causing the massive locomotive to derail in a spectacular crash. The Dawn of Tragedy

The story ends not with a victory, but with the heavy realization of the gap between the slayers and the Upper Moons, leaving Tanjiro more determined than ever to grow stronger.

The story follows , a young boy who breathes through a blade to protect his demon-turned-sister, Nezuko . Alongside his chaotic companions—the fearful but lightning-fast Zenitsu and the wild, boar-masked Inosuke —Tanjiro boards the steam engine to meet the Flame Hashira, Kyojuro Rengoku . The Dream Weaver

Rengoku engages him in a duel of pure elements: . Despite Rengoku’s legendary skill, Akaza’s demonic regeneration gives him the edge. In a final, heart-wrenching stand, Rengoku pins the demon to his chest as the sun begins to rise. Akaza flees into the woods to escape the light, leaving a dying Rengoku to impart his final words to Tanjiro: "Set your heart ablaze."