Classes: Warrior, Druid, Paladin, Death Knight In Raids (10 people and more), more than one tank is usually available. In these cases, one tank becomes the MT, and the others are designated off-tanks. An OTs job is usually to be second on the aggro list of the mobs, so if the MT dies, he's able to quickly draw aggro and replace the MT. Where an offtank is present, it is also the best idea for the offtank to intercept a lone target-changing mob, so the main tank can handle the other X number of mobs.