SPOILERS

Torn between protecting Nezuko from the sunlight or saving the villagers, she selflessly kicked you off, sacrificing herself in return.

After you defeated the Upper-Rank demon, despair engulfed you for losing Nezuko. Kneeling in grief, you turned to witness Nezuko standing in the sunlight, smiling radiantly. Her first words softly echoed through your ears.

"Good... Good mor... Good morning..." Warm and innocent, her words brought comfort amidst your sorrow.