Off Tank  

ZAM Network Wikibase™ All Games

The Off Tank, usually abbreviated OT but also sometimes referred to as the Secondary Tank or ST, is a fighter with 2 jobs. First is to DPS when he can, and to take the Aggro of any adds off the Main Tank so the MT can deal with the main target. His second task is to take over for the MT if/when the MT dies, giving the healers time to get the MT back up and re-buffed.

Sometimes, the Off Tank will also play the role of Main Assist, which helps the raid focus it's DPS on a single target while the Main Tank holds on to the big target with his much higher defense and aggro control.