Tsubaki Nakao crafts desserts and develops the sweet menu, including original creations, as the pâtissier for the Japanese-style tea house Rokuhōdō. Despite his pastry expertise, he remains intensely introverted, visibly wilting under direct attention or praise. This shyness vanishes among his Rokuhōdō colleagues, where he readily engages in friendly arguments and frequent mutual teasing, particularly with the barista Gure.

Driven by an extreme sweet tooth, Tsubaki independently visits other cafes to sample their dessert buffets and offerings, blending personal enjoyment with professional research. His dedication extends to mentoring; he guides magazine writer Hirokazu Isago in overcoming self-consciousness about solo cafe visits, earning Tsubaki the respectful title "Master" from Isago.

Renowned pâtissier Eisuke Tsunozaki, affiliated with the East Side Grand Hotel, explicitly praises Tsubaki's talent to Sui, noting Rokuhōdō secured a significant asset. Tsubaki freely shares his knowledge beyond the cafe, such as teaching young customer Kotsuru Amagami to make matcha ice cream so she could share it with a friend.