Despite major losses, all of the members of the Twelve Kizuki are slaughtered and the Infinity Castle is destroyed, leaving only the Demon King, Muzan Kibutsuji left. However, Muzan is now stronger than ever before—pitting the remaining Demon Slayers into their toughest fight yet.
Tropes present in Sunrise Countdown Arc:
- The Bus Came Back: After spending the entirety of the Demon Slayers' battles against the Twelve Kizuki and Muzan on the sidelines due to slowly transitioning back to her human form, Nezuko shows up just moments her older brother becomes a Demon.
- Character Death:
- Gyomei, Mitsuri, and Obanai are the Hashira that perish from their injuries after Muzan is defeated.
- After a millennia of terrorizing Japan alongside his kind, Muzan Kibutsuji, the Demon King, is finally vanquished—even his will on Tanjiro doesn't last, as his consciousness falls to the deepest pit of Hell upon Tanjiro turning back into a human again.
- Subverted very heavily with Tanjiro. It's because of Muzan temporarily turning him into a Demon that he is revived, even after he is turned back into a human again!
- Final Battle: All of the remaining members of the Demon Slayer Corps (including the Kakushi) are once again pitted against the Demon King, now more powerful than ever before. However even after Muzan is stalled enough to finally be wiped out by the sun, his cells fuse with Tanjiro, who becomes the new Demon King (albeit for a brief short time before Kanao cures him with Tamayo's remaining vial).
- Hourglass Plot: Nezuko sees Tanjiro as a Demon just after she is turn back into a human, paralleling how human Tanjiro had to witness Nezuko slowly turn into a Demon for the first time.
- Post-Final Boss: The battle against the Demonized Tanjiro is much shorter (with less major casualties) compared to Muzan, mainly due to him being in a feral state and Kanao quickly injecting him with the last vital to turn Tanjiro back into a human.
- Superior Successor: It's all but certain that Tanjiro would be an even more powerful Demon King than Muzan—considering he has all of the latter's power combined with sun-based abilities, prior skills in swordsmanship, and especially the ability to survive the sunlight. It's a good thing Kanao had the last vital from Tamayo and Shinobu, otherwise the entire remaining Demon Slayer Corps (and probably the rest of the world) would be good as dead.
