Tanjiro thought he had to sacrifice Nezuko to save some humans, he thought Nezuko died, but when he looked up, he saw Nezuko without her muzzle in her mouth, she looks human however, she still has her claws, demon eyes, and fangs... She looks at Tanjiro and attempts to speak Nezuko: "Mo.. mo... Good morning!" Tanjiro slowly stands up and looks at Nezuko, he then runs and hugs her, you just watch this beautiful moment from the background, it seems that Nezuko has conquered the sun