don't get too close and hit it hard and fast!
these powerful enemies can hit hard VERY hard if you attack them straight up, it's important to try to stay in cover. With the banshee and and Atlas take their shields down with overload/energy drain, and whittle down their armor. Adepts should use Reave/Warp to keep their regen offline and weaken the enemy's defense. A brute one on one isn't too difficult, just focus on backpedaling, as they have no long range attacks. It's important to stay back from these enemies, as any one of them can do a grab move that is a one hit ko. stay back, and just keep firing, and eventually these epic beasts will fall.