Despite fighting Tanjiro for almost the entire Demon Slayer era, Nezuko does not seem to be revered as a full-time Corps member. Will Nezuko be a demon killer?
Nezuko joins the Demon Slayer Corps as an honorary member. Before Rengoku’s death, he gives her his blessing as a member, and another Hashira comes to receive him, even though they do not show it.
He will have to earn the respect of each Hashira over time. Considering how recently he became a demon, the confession could not always come as hard as Rengoku or Giyu did.
Rengoku allows Nezuko Become A Demon Slayer
Rengoku risked his life to protect young demon killers, and civilians who rode the Infinity Train from Upper Moon Demon He Came to Chapter # 66. He managed to delay Ahaza until the morning, and he fell with a deadly wound on his stomach. Rengoku uttered his parting words in Tanjiro, naming Nezuko a member of the Demon Slayer Corps.
Tanjiro… I believe in your little sister. I consider her a member of the Demon Slayer Corps. On that train, I saw her shed her own blood to protect humans. If she risks her life to fight demons and protect people, she’s a member of the corps, no matter what anyone says!
Rengoku to Tanjiro | Chapter #66
Nezuko never carries or wears an official sword or Corps uniform. He works for the Corps because he stays with Tanjiro, who bears the brunt of any possible consequences for Nezuko’s assignments.
One Hashira was initially unhappy with Nezuko’s decision to join the Corps. Nezuko was chased away by the Snake and the stone Hashira. The spirit Hashira, especially Sanemi, had little faith in Nezuko and her ability to help them in any way.
Is that the idiotic Corps member who travels with a demon?
Sanemi to Tanjiro | Chapter #45
Sanemi cut off Nezuko’s carrying box of walking with her knife. She tried to figure out how to deal with the pain and human blood, but Sanemi refused when Nezuko managed to fight this.
So you have it. Rengoku sees Nezuko’s transformation into a demon killer even if it takes longer for any other Hashira to show respect.