Just a small comment on a single minor point here:
The present-day speakers of Slavic languages are not all descendants of a single ancestral stock. In central Europe they come from multiple non-Slavic ancestral stocks: Celts, Balts, Germans, Scandinavians, Finns, Estonians, etc. etc. In North-Eastern-most Europe, chiefly in Russia, where the use of Russian became wide-spread only in historical times, the underlying ancestral stocks include many more non-Indo-European ones than just Finns and Estonians. In consequence of this, the pre-Christian pantheons and religions of the peoples who now speak Slavic languages, so far as we can find traces of them in the oldest records, were many and varied, not a single unified thing. Many or all of these regional variations may not have been Slavic originally. Any "Slavic" pantheon you may find described in books is no such thing in actual fact, but a semi-scholarly blend of disparate pieces of evidence. (The "semi-scholarly" shoe often fits even when some of the authors were eminent academics. The best scholars confine their reconstructions to very small territories or social circles.)
no subject
The present-day speakers of Slavic languages are not all descendants of a single ancestral stock. In central Europe they come from multiple non-Slavic ancestral stocks: Celts, Balts, Germans, Scandinavians, Finns, Estonians, etc. etc. In North-Eastern-most Europe, chiefly in Russia, where the use of Russian became wide-spread only in historical times, the underlying ancestral stocks include many more non-Indo-European ones than just Finns and Estonians. In consequence of this, the pre-Christian pantheons and religions of the peoples who now speak Slavic languages, so far as we can find traces of them in the oldest records, were many and varied, not a single unified thing. Many or all of these regional variations may not have been Slavic originally. Any "Slavic" pantheon you may find described in books is no such thing in actual fact, but a semi-scholarly blend of disparate pieces of evidence. (The "semi-scholarly" shoe often fits even when some of the authors were eminent academics. The best scholars confine their reconstructions to very small territories or social circles.)