Toxic shamans function in two ways, as Poisoners or Avengers. Poisoners are totally corrupted. The environment that created them is what they seek to make the rest of the world into (usually) as a result, they will attempt to corrupt the environment in a manner they see fit. Posoners often follow the will of their totem in the exact opposite manner. A dog shaman, for example, is rabid and wil probably destroy their friends and allies. An eagle shaman seeks corruption. A bear shaman will seek to maim and kill instead of heal. Shark shamen become even more brutal and vicious, murdering as much as possible. Essentially poisoners are rabid, psychotic versions of their former Totems.
Avengers on the other hand, are just that, on a quest for revenge. They often seek to destroy those whom have harmed them, often resorting to manners that are more harmful than good. An avenger's quest is typically to destroy polluters and corrupters. An avengers totem is essentially a vengeful form of their former totem, focused but still rabid.
Toxic Shamen are empowered by Potency, an extra dice pool to use in Magical skill tests. Potency is gained when a Toxic shaman accomplishes a goal. The higher the potency, the more terrible the agenda. These objectives are based on the type of shaman they are (Poisoner or Avenger) and their specific totem. Urban totems will seek to destroy or avenge man's spirit while nature totems will protect or destroy the land. If an agenda is foiled, the Shaman's potency decreases. So if the runners encounter a powrful shaman they can weaken them over a series of adventures instead of one all-out battle.
