The second season of Kimetsu no Yaiba (Demon Slayer), presented us with amazing matches in which, despite his incredible strength and heroic efforts, Tengen Uzui was in a bind, as he needed a lot of help to defeat Gyutaro.
Something that we find quite curious is that, the sixth upper demon moon proved not to be easy to beat in the Red District arc, almost claiming the life of a Hashira from beyond the grave. Gyutaro’s deadly poison came only moments away from killing Tengen before Nezuko’s bloody technique saved the Sound Hashira’s life.
Although Tengen is considered one of the weaker Hashira, perhaps rightly so, there is little reason to believe that most others would have fared better against Gyutaro. This is a former shinobi with resistance to poison and he still struggled to combat the effects of poison well enough to keep fighting effectively.
Assuming none of the other Hashira can resist the poison and stop their own hearts from spreading, that only leaves one who could have defeated Gyutaro and survived his poison without Nezuko’s help: Shinobu Kocho. She is a medical expert who could find a cure with some ease.
Shinobu Kocho, is an expert in all things poison and was shown in Kimetsu no Yaiba’s “Natagumo Mountain” arc to always carry various antidotes with her. Considering that even Tengen’s resistance to the poison wasn’t going to save him from Gyutaro’s, any Hashira other than Shinobu who was attacked by Gyutaro would face certain death.
Shinobu, the hashira who could have survived the demon poison
Shinobu is physically too weak to decapitate demons, but she is blindingly fast and uses her special sword to inject demons with Wisteria poison. Wisteria poison is a substance that is actually capable of killing them with a large dose.
Shinobu Kocho, the insect Hashira, makes up for her lack of strength with incredible speed and a large amount of poison, so she would have probably had an easier time fighting Gyutaro and Daki than Tengen. All he would have to do is stab each of them once and wait for them to die from Wisteria’s poison.