I think "wolve" is the verb Please Register or Log in to view the hidden image! (Compare half, halves, halve.)
I have seen wulv online, as a sort of hybrid between the Scandinavian "ulv" (meaning "wolf") and the English word. The word "wolf"—in that spelling or as "wulf"—has been round since the day of Old English, with the "f" intact, otherwise. The v in wolves comes from the fact that the f in the Old English plural (wulfas, and later wolfes) was "voiced" as opposed to the unvoiced f in Modern and Old English word wolf. Because of the voicing, the substitution of a v for the f was a common change (and happened with the Old English-derived words "half" and "calf" as well) when spellings standardized.