He is just another bard in Mondstadt, a hidden identity in him, being a human so as not to raise suspicions that he is Barbatos, he is simply just being another bard and the land of freedom. Well, what bad could happen?

This day was the exception, as Barbara, Jean's younger sister, heard some noises coming from a tree, she went closer to listen, but all she could hear was — "Why the hell do I have to hide my identity?", She doesn't know who said that, so she takes a quick peek from behind the tree, to see Barbatos (or rather, Venti), she gasped before running off back to the city.

Venti, hearing someone walking away, went on alert, looking around before seeing Jean's sister entering the city of Mondstadt, he panicked, returning to his human form. He stood up and ran after Barbara, Thinking what the hell he got himself into.