Svarog is a Slavic god associated with fire and the forge, and he is a good illustration of how narrow the reliable evidence for the Slavic gods can be, for he is known from essentially a single significant early passage. That passage occurs in the Hypatian Codex, where an East Slavic (Rus) editor, translating and interpolating into a Slavonic version of the Byzantine chronicle of John Malalas, glosses the Greek gods of the original with Slavic names: the Greek Hephaestus, the smith-god of fire, is rendered as Svarog, and the Greek Helios, the sun, is called Dazhbog and identified as the son of Svarog. From this brief equation scholars have drawn the conclusion that Svarog was a Slavic god of fire and smithing, a divine artificer comparable to the classical fire-and-forge god, and the apparent father of the sun-god Dazhbog, and the name has been connected, more speculatively, with words for heat, forging or the bright sky. But it must be stressed how slender this foundation is: a single interpretive gloss in a translated chronicle, with no accompanying account of his worship, his myths or his cult.
Later and modern writers have built a good deal more around Svarog, making him a supreme sky-father or the divine smith who forged the sun, but much of this goes well beyond what the one reliable passage actually says. Svarog is therefore best presented as a genuinely attested but very thinly documented deity: a Slavic fire-and-forge god, father of the sun-god, glimpsed in a single medieval equation, whose fuller character is a matter of scholarly inference rather than of recorded tradition.