Nezuko Kamado

She sat by the window and waited for Tanjiro to return.

She has also developed a strong willpower, which can be seen through her refusal to consume human flesh or blood, even in cases of extreme injury or exposure to human blood, which can be seen when she refuses Sanemi Shinazugawa after he attempts to lure her into biting him with his Marechi blood.
Her strong willpower remains even when she is no longer a demon, as shown when she willingly leaps in front of Inosuke to protect him from her own brother, who had become a demon and was attempting to kill those around him. Though she could have been killed, Nezuko did not hesitate to protect her brother.
On the rare occasion that Nezuko attempts speech, she has been seen to stutter a lot, which may be due to her bamboo mouthpiece, which is seldom removed, and the fact that she didn't speak for a number of years after her transformation. However, after developing resistance towards sunlight, which allows her to go outside and interact with others more often, her speech has shown signs of improvement, and she is able to fully pronounce words if someone else has just spoken them, or hears them repeated frequently enough.
It was later revealed by Tamayo that her missing memories and underdeveloped personality were due to her not being fully conscious, as she prioritized developing her resistance to the sun over regaining her consciousness.
Abilities: Despite not being a member of the Twelve Kizuki, Nezuko is a very powerful demon. Her most prominent trait is her extraordinary growth rate, due to the high amount of blood she received from Muzan Kibutsuji when he turned Nezuko into a demon. This was shown in many battles where she could defeat her enemies despite being overwhelmed by them in the beginning. She has been shown to defeat her enemies by increasing her own physical capabilities, enhancing her regeneration, or developing her own Blood Demon Art in dire situations.