Balak

Ka'hairal Balak is a Batarian terrorist attempting to crash Asteroid X57 into the human colony, Terra Nova, below. Commander Shepard confronts Balak and his soldiers in battle after stabilizing the asteroid. Sacrificing the lives of the scientists Balak used as hostages, Shepard engages to terrorist in combat.

Mass Effect
After shutting down all three fusion torches, Shepard goes to the main facility and confronts Balak and his remaining team. Balak gives the Commander an ultimatum, let him go or let the scientists Balak captured die. Determined to stop Balak, Shepard states that the Balak will be stopped and that killing the scientists will be the last thing he does. Balak then activates a bomb, killing all the hostages in the other room and engages Shepard in combat.

Shepard then guns down the rest of Balak's terrorists, varren and defense drones. A wounded Balak then states that Shepard is no better than him by throwing those innocent scientists lives away. Shepard can then choose to either leave him for the Alliance, let him die or outright kill him. Whatever fate you choose for Balak's, will have consequences for subsequent games.

Tactics

 * Balak is essentially a stronger version of the Batarian Trooper.
 * He will rely heavily on Immunity to defend himself and advance from cover to cover to attack.
 * With his other guards and drones assisting him, the overall fight may prove to be a challenge, but Balak alone is not especially difficult to defeat.