Tamayo/Relationships

Yushiro
It's unknown how these two met, but it was most likely due to Yushiro's unknown illness that was unavailingly treated by Tamayo. When he was about to die, Tamayo asked him if he either wants her to save his life by turning him into a Demon or to let him succumb into his illness. He decided to become a Demon, and since then, Tamayo took him in as her personal assistant and a medical practitioner. He also developed strong romantic feelings towards her, becoming very possesive of her, to the point of becoming angry when someone was even dwelling too close in her presence, hitting Tanjiro multiple times (which deeply annoyed her) and becoming visibly distressed seeing Tamayo being hugged by Nezuko. However, these feelings weren't reciprocated since Tamayo never get over loss of her husband and children.

After sensing Tamayo's demise from Muzan's hands, Yushiro became deeply angered and swearing to kill Muzan by any costs.

Kagaya Ubuyashiki
It's unknown how these two met or what their relationship is, but after Tanjiro's trial before the Hashira is over, Kagaya tells Tanjiro to give her his regards as Tanjiro is carried away by two kakushi towards Shinobu's house, also known as the Butterfly Mansion.