Perun is the Slavic god of the sky and thunder.

Svarog is also the god of the sky, but his function is not identical to that of Perun. Svarog is rather seen as a god of the universe and the spirit, "immaterial" heaven, where the dead reside. It could be said that Svarog rules in high heaven, while Perun - in low heaven that is Svarog is the god of the universe, while Perun is the god of the atmosphere. Perun is one of the most powerful Slavic gods. He punishes disloyalty and all bad people. He is related to justice like any deity who has ties with Jupiter. He punishes wicked and disobedient people closing the door of heaven for them. He punishes disloyalty and for the enforcement he often uses the lightning. The name Perun derives from suffix "-un" or "-UNJ" (-yнь), which means "one who must do something", and from the root "per-" which means to strike, destroy.

So Perun means "he who strikes, crushes and thunders" and even "the god of destruction and demolition."

That's why he is given the power to unleash natural disasters. The legend says that when Perun was riding in a chariot, the sound of the wheels represented the thunder. Perun was described as a strong man with a beard. The clothes are reasons to believe that he was a warrior in armor, as for most of the Slavic gods. Perun is also represented with a stone sword with which he hits and transforms into a stone everything what he touches. Furthermore, he is represented with a bow, once identified with the rainbow, and, when he pulled, the arrow turned into a thunderbolt. He also had the golden apples. Some legends tell about a conflict between Perun and Veles. Veles  had stolen women, men and beasts from Perun. Veles tried to hide but Perun, after breaking the stone behind which he had hidden, found him and defeated. This Belarusian legend tells that Veles was forced to remain on the earth. However, another legend said that during the marriage of Perun with Dojdola (goddess of rain), Veles had caught the eye of the goddess and declared his love to her. After that conflict with Perun, Veles was defeated and exiled on the earth and finally found his place in the underworld.

Perun was also associated with fire and fire animals.

His animal was a cock of fire, a sort of Slavic Phoenix. Among his pets there were also dragons. His rites were related to the fire. Near his idol the eternal fire was burning, it should not be turned off in any case (a similar custom existed in ancient Greece, the temple of Hestia, or Rome, the Temple of Vesta). Perun also fought against drought. Some say that Perun had the power to command the rain, others argue that this power had his wife Dojdola. In any case, Perun could not do much about this.
Despite attempts to destroy him, his name remained. In addition, Perun is one of the gods who is the best known and most remembered by the Slavs.