Vidar

In Norse Mythology, Vidar was a son of Odin and Grid (a giantess), and had a twin brother named Vali. He dwelled in Vidi. He was one of the strongest of the gods and can be considered a god of vengeance. In the Ragnarok he will avenge his father by killing Fenris. He is one of the Aesir who will survive the final battle.

Source: Nicole Cherry, A list of Norse Beings, originally at www.ugcs.caltech.edu/~cherryne.
Copy still available at www.angelfire.com/wy/wyrd/list.html