From the White Wolf Wiki, the most complete White Wolf reference

The Wyld is one of the three spirits of the Triat. The Wyld creates absolute chaos, which is given order by the Weaver before it is destroyed and returned to chaos by the Wyrm. Where the other two of the Triat went insane, the Wyld is diminishing, being squashed out by the Weaver, and destroyed recklessly by the Wyrm.

Black Furies and Red Talons are the two foremost Garou tribes who celebrate the Wyld.