Tanjiro and the Hashiras are attempting to keep Muzan occupied until dawn in order to kill him completely. Towards the end of the fight, the main antagonist of Demon Slayer, Kibutsuji Muzan, perishes. Moments before dying, he reaches for Tanjiro and transfers all of his blood into his body. Just before injecting blood into Tanjiro, he stopped breathing and was dead for a few seconds. Tanjiro comes back to life and turns into a Demon far more powerful compared to Muzan, his morals are gone.