What is "vikar"

Víkar ( Old Norse nominative case form Víkarr; Latin Wicarus) was a legendary Norwegian king who found himself and his ships becalmed for a long period. To raise a wind, a human blood sacrifice was needed, and the lots fell on King Víkar himself. Starkad (Starkaðr), Víkar's counselor urged a mock hanging from a tree instead, but in giving this advice Starkad had been prompted by the god Odin, who desired Víkar's death. According to the account in Gautreks saga, when Starkad let loose the branch, the apparent reed-stalk with which Starkad stabbed at the king was seen to be a real spear, the stump under Víkar's feet fell away, and the calf guts which had been used instead of rope turned into a strong withy. Víkar died. Saxo Grammaticus in Gesta Danorum (book 6) refers to a similar version relating a magic transformation, but prefers or invents a more rational account in which Starkad tied the osier very tightly so that Víkar could hardly breathe and then stabbed Víkar with his sword. This was the first of Starkad's three great crimes.