Vidar: the Norse God of Vengeance

Sometimes called the "Silent God," Vidar was the Norse god of vengeance and the second strongest god in all of Norse mythology, second only to Thor, as is stated in his entry in the Prose Edda: "One is called Vidar; he is the silent god. He has a thick shoe and is nearly as strong as Thor. The gods rely on him in all difficulties." To be clear, strength here is only physical strength, strength not used as a byword for power, for the most powerful god, when you factor in everything, not just battle prowess, is undoubtedly Odin, who, incidentally, was Vidar's father, siring him on the giantess Gridr. She at one time lent Thor a number of armaments, including her belt, staff, and iron gloves, which helped him ford a river and defeat the giant Geirrod. It isn't known for certain why Vidar was silent, but it has been posited that it is connected to ritual silence and other abstinent behavior in relation to vengeance, those committed to the path of vengeance refraining from speech and other indulgences until their quarry was killed. Another example comes from the god Vali, who stopped washing his hands and combing his hair until the body of the one he vowed to kill blackened on the funeral pyre. Unsurprisingly, Vidar's most important contribution to Norse mythology is a heroic act of vengeance, which is exactly what you would expect from the god of vengeance himself. Said most simply, he avenges his father by ripping a giant wolf's head apart. However, to understand how important this avenging was - that is, how death-defying and world-saving it was, Odin's honor being the least important aspect of this - a lot of information has to be layered on top, answering questions like: Who was this wolf? How was this wolf possibly powerful enough to kill the king of the Norse pantheon? Why Were Odin and this wolf even fighting? And how did Vidar, though a very powerful god, manage to kill the monster that killed Odin, the most powerful of the Norse gods?