Slavic Mythology

Hello, i was wondering if anyone here is interested in slavic mythology or paganism? I drew my new OC, Lucien, and i thought i'd link his "christian" parts to slavic mythology by making him one of the slavic demons - Bies, and i wanted to find more info about it but there isn't much on google :/ does anyone know some good sources that i could use to base his backstory on? I want to know more about Biesy so i can make him as accurate as possible :) All i got is that they usually live in forests or swamps, they get out on fields in spring to hunt, and that you can kill them by throwing a consecrated (?) knife

Thank you in advance :))