At the start of the battle, Wargar Guardians will charge up to your perch. Stay protected behind the stone banisters and engage the Guardians as they climb the stairs. Deal with the Guardians first, then turn your attention on the Infected Wargar below. They volley explosive blasts up at you. Traverse up and down the stairs to avoid the enemy fire as you return ranged fire. It may take a while, but the vile creatures will fall if your aim is true.
There's a secret treasure vault in the temple. Find the circular symbol on the ground in front of the elevator platform. Light the arrow in the nearby brazier, turn around, and look up. You'll spot a gargoyle on the roof holding a brazier. Shoot the brazier with a fire arrow. A wall opens beneath the entrance landing and reveals a treasure chest being guarded by...a chicken.
With the Infected Wargar dead, cross to the temple's far side and climb up to the skeleton on the slab in front of a large silver symbol. When both Caddoc and E'lara step onto the circular area surrounding the skeleton, the whole platform sinks. When the ride ends, retrieve another Crystal and jump down from ledge to ledge until you reach the cavern's bottom. A second Crystal Chest at the base is the reward for your cliff-jumping exploits. Continue down the passage to the next obelisk, then jump off the final ledge when you're ready to face the Queen of Darkness.
Apparently, the Sleg didn't fill up the Queen of Darkness. She's hungry for some more sustenance, and you're the only thing in sight. The giant spider attacks you, and her mighty weight triggers an earthquake around you.
Sprint for the first brick wall. The giant spider chases you, and if you delay for more than a second, she eats you. When you reach the wall, the earthquake will topple the wall and you can charge on.
Dodge the Arackling Crawlers and Wargar Soldiers in the next area. You can't afford to fight any of them. Continue to sprint for the next brick wall and run through when it crumbles.
Sprint for the stone archway, which will temporarily hold the creature back.
Look for the ballistae perched in the distance. These are the only weapons that can hurt the monstrous spider. Climb behind one of the ballista and begin firing at the beast.
Continue firing at the Queen. You must whittle down half her health before she breaks through the stone archway. Unfortunately, the ballista takes a few seconds to reload, so you can't afford to miss.
If you deal enough damage to make the Queen stagger, you have a couple seconds to notice a stalactite hanging precariously above the creature's body.
Two ballista hits break off the stalactite, which skewers the Queen of Darkness's head. The creature writhes around and dies in an explosion of goo.
Seraphine appears and warns you that the Wargar have taken the prisoners, including her physical body, out of the dungeons and into the Wilds of Govad. It looks like the chase has now gone outside into very dangerous terrain.