A Description of Kanao and Aerith's Friendship
Aerith lost her parents at a young age because of a demon attack, and Kanae Kocho arrived just in time to save her. Growing up in the Butterfly Mansion, she and Kanao bonded like sisters. Aerith is well aware of Kanao's love for Tanjiro and is a hard-core shipper, trying to get them to confess their feelings for each other just like Nezuko.
Spoilers Alert for the demon slayer manga. You have been warned:
Aerith dies in the final battle against Muzan and the Upper Ranks and Kanao was devastated, feeling that she lost a part of herself. 😔