Unwanted Guests

Quest Overview
Summary:
 * 1) Clear The Labyrinth of the invading Dryder Force. you have 6..0 groups remaining.
 * 2) Return to Reaper of the Labyrinth for your reward. [sic].

Obtained from:
 * Reaper of the Labyrinth in The Underworld

Requirements:
 * Clear the Chamber

Reward:
 * 10,000 XP

Dialogue:
 * "The stench of the Terrorwebs still lingers in the Labyrinth. The Vengeful Aatxe have been enchanted by a Keeper of Souls. No blade, hammer, or spell in any world can do harm to them while the Keeper lives. Kill the Keeper to disable his potent magics, and the Vengeful aatxe will follow him into death. If you do this, the death god will look upon your actions and smile"

Followup:
 * None

Walkthrough
A few tips for successfully completing this quest:
 * Before Accepting this quest make sure you clear the entire Labyrinth.
 * Make sure you do not have the Escort of Souls quest running concurrently.
 * After accepting this quest six different groups will spawn throughout the Labyrinth. Each group consists of one Keeper of Souls, three Terrorweb Dryders, and three Vengeful Aatxe.
 * Don't target the Vengeful Aatxe before the Keeper of Souls in their group is destroyed, since they are invulnerable to any attacks beforehand. Knockdowns and cripple still affect the Aatxes, so it might be wise to use them if you have to fight the Aatxes.
 * Kill the Terrorweb Dryders if they are preventing you from safely reaching the Keeper of Souls.
 * Once the Keeper of Souls is dead, the Vengeful Aatxe should also die instantly. If they do not, have the tank continue tanking while the rest of the party moves to a safe location. Once everyone is out of danger, have the tank follow so that the Vengeful Aatxe break aggro and die. If the tank is having difficulty keeping the Aatxes from attacking the Reaper after he shakes them off, he can always sacrifice himself. Once he is resurrected he can simply accept reward to remove Death Penalty. If you are already able to teleport, teleport to anywhere and the Aatxes will also break the aggro.
 * The best approach to this quest is to first free both the Reaper of the Forgotten Vale and the Reaper of the Ice Wastes. Then accept the quest and use the teleport function to attack the Keeper of Souls from behind. Be sure to study the patrol patterns of the monsters if you aren't familiar with them.