Son of LOKI and SIGYN and used by the Gods to extract a terrible revenge for the death of BALDUR.
By some kind of Fenrisization, he was turned into a wolf, encouraged to attack his brother NARVI and tear his throat out.
The entrails of NARVI were used to bind LOKI to rocks. They seemed a bit stretchy so the Gods turned them into iron and then SKADI came up with the idea of the venom-dripping snake.
We don’t know what happened to VALI(2) after this. He probably ran off into the woods to become a run-of-the-mill werewolf.
See also: VALI.