Overseer Markus is the fist boss that you will come across inside of the Deepstrike Mines. He has 27,594 health and come with four Rotted Dredger adds. AoE down the adds on the pull then focus on Markus himself. At 50% health he will split into three Shade of Markuss. Have your tank mark each one in turn and focus fire them down. After the three shades are dead Markus comes back and you can finish him in normal tank and spank fashion. Return to Torin Fergal for your well earned reward.