Nezuko is a formidable devil. Muzan Kibutsuji gave her a lot of blood when he turned her into a demon, and the fact that she doesn't need to eat humans to survive is another reason why she was able to grow so swiftly. Despite being outmatched at first in a number of the series' confrontations, she managed to overcome her opponents.

As the "chosen demon," Nezuko is distinguished from other demons by her special demonic traits. Most significantly, unlike other demons, Nezuko can restore her power without consuming people. Rather, she can only replenish her vitality by sleeping. To recuperate and regain her vigor, though, she would require a protracted period of rest.

In Episode 6, while battling Daki, Nezuko changed into an Awakened Beast. Nezuko is capable of going wild. She changes into an adult version of the darkened version of herself, covered in tattoos that resemble vines and sporting a single horn growing out of the side of her head.
Nezuko now possesses remarkable physical prowess and, at the expense of consuming human blood, has improved her rejuvenation to the level of the Upper Ranks.

During their battle with Upper-Rank Four, Hantengu, Nezuko acquired a resistance to sunlight—a feat that would have been unthinkable for demons, including the Demon King himself. Because of her immunity to sunlight, she may move and walk throughout the day without getting burned to ashes, which forces Muzan to rethink his plans and pursue and absorb her in order to become the sun's ruler.