Containment
Controllers are the masters at locking down and controlling their opponents. Few can escape their will. Controllers do extra damage to any target that is already Held
Control powers do not generally exist in T3; those who do exist are costly and geared towards non-combat situations. Rather than add a host of such powers, controllers and dominators use regular powers, only exchanging damage for control.
Any Wound Point inflicted by a Controller are halved, but each damaging attack also costs the target 3 shots. Once the target is out of shots, containment kicks in and it is all damage.
Build
A controller uses Sorcery skill and Sorcery schticks. This gives controllers a great diversity of powers.