Barbara’s reference is the character from the Genshin Impact Game series

Genshin Impact is an action role-playing game developed by Chinese developer miHoYo, and first published in 2020. The game features an anime-style open-world environment and an action-based battle system using elemental magic and character-switching.

Barbara is a playable character. She was Deaconess of the Church of Favonius, as well as the shining idol of Mondstadt. In fact, Barbara can do much more than just put people in a better mood: Her healing powers extend to flesh wounds and other physical ailments.

Every citizen of Mondstadt adores Barbara. However, this has not always been the case. At first, Barbara's songs sounded strange to the citizens of Mondstadt, and many struggled to see the appeal. This was because, for the longest time, the folk songs of bards were the only popular songs known in Mondstadt. Fortunately, Mondstadt stayed true to its reputation as the City of Freedom, and the people ultimately embraced the new while continuing to cherish the old. People accepted Barbara's songs, and over time her positive energy rubbed off on them. Soon, they could be heard humming her tunes all around Mondstadt.