Vidar (pronounced “VIH-dar”; from Old Norse Víðarr, which might mean “The Wide-Ruling One”) is one of the younger generation of gods who survive Ragnarok, the cataclysmic end of the cosmos in Norse mythology. (In some accounts of that event, that is; in other accounts, the universe just ends, and no one survives.) Virtually all of the references to him in Old Norse literature are concerned with his role in Ragnarok; we know little to nothing of his personality or function outside of that one particular episode.
During Ragnarok, the gods – the divine forces who uphold the cosmic order – and the giants – the divine forces of chaos and destruction – battled, and most of those involved on both sides were slain. The god Odin was devoured by the wolf Fenrir. Vidar, a son of Odin by the giantess Gríðr, immediately set upon the wolf to avenge his father’s death. He wore a shoe that had been crafted for this particular moment. It was the strongest and sturdiest of all shoes, and surely also charged with magical properties. With it, Vidar kicked open the wolf’s lower jaw, and then, holding the beast’s upper jaw open, he sliced Fenrir’s mouth to pieces with his sword, killing the monster and ending his devastating rampage.
Elsewhere, Vidar is called the “silent god,” although no explanation for this epithet is given. He is said to be the strongest of the gods after Thor. His land is described as a place of brushwood and tall grass, but the significance of the association of this particular kind of landscape and this god is unknown.
Two place-names from Norway contain his name: Virsu (from Viðarshof, “Temple of Vidar”) and Viskjøl (from Víðarsskjálf, “Crag/Pinnacle of Vidar”). This seems to suggest that Vidar featured in pagan Norse religious practice, and that he wasn’t just a literary figure.
Turning to the archaeological record, depictions of a man tearing apart the jaws of a wolf on the Gossforth Cross from northern England and the Kirk Andreas Cross from the Isle of Man, both of which date from about 900 AD, could be Vidar and Fenrir. But they could also be Christ and a more general wolf, since Christ triumphing over various monsters was a popular motif in medieval art, and artists often freely mixed pagan and Christian imagery in the same works. Even if these are representations of Vidar and Fenrir, they provide us with no new information, but merely an additional corroboration of a motif that’s repeated often enough in the literary sources to leave no doubt regarding its authenticity.
Unfortunately, then, we know of Vidar only as the avenger of Odin and the slayer of Fenrir. The few other tantalizing but wayward details don’t add up to any particular, let alone comprehensive, portrait of a personality or mythological/religious role. Sadly, the question of who exactly Vidar was to the pre-Christian Norse and other Germanic peoples is essentially unanswerable.