What is "chernobog"

Chernobog ( and *bogŭ "god"), also spelled as Chernabog, Czernobog, Chornoboh, Crnobog and Tchernobog is a Slavic deity, whose name means black god, about whom much has been speculated but little can be said definitively. The only historical sources, which are Christian ones, interpret him as a dark, accursed god, but it is questionable how important or malicious he was really considered to be by ancient Slavs. The name is attested only among West Slavic tribes of the 12th century, hence it is speculated that he was not a very important or very old deity. Older scholarship assumed him to be the counterpart of Belobog.