The Mines of Kaderak (Part 2) - Act 3 Story Quest
The Mines of Kaderak (Part 2) is the 5th Story Quest of Act 3 and begins immediately following your completion of The Mines of Kaderak. For the first part of this quest all you need to do is run along the linear path through The Mines of Kaderak pulling all the levers as you go which will move the mine cart along the tracks.
Your goal is to get the mine cart to the end of the tracks where it'll crash into the Soul Shard and destroy it. While hitting the levers to advance the mine cart you'll also want to explore the areas around you as there are many secrets to be found and a few Side Quests that you can complete if you'd like.
Side Quests In Area:
While exploring the Mines of Kaderak I strongly recommend you destroy all of the red barrels you come across with a ranged character in your party (if you have one). These will instantly kill a character if they blow up next to you - much like how they instantly kill enemies when they're close enough. I find it better to get rid of these early so they don't accidentally go off and take any team members out.
After you press enough levers in the Upper Mines of Kaderak and crash the mine cart into the Soul Shard you'll now want to head into the Lower Mines of Kaderak. Our route down to the lower mines is quite linear as the path from Upper Mines of Kaderak will funnel you right into the lower mines.
In the Lower Mines of Kaderak you'll find the location that Vix's Vengeance is completed as well the path that leads to the boss trio of this area, the Dark Wizards of Valdis.
The fight with the Dark Wizards of Valdis will be very similar to the fight against the solo Dark Wizard of Valdis during the Princess Evangeline Story Quest. Much like with all boss fights you're going to want to switch your party to 'Mirror Mode' for this entire fight.
One of the new abilities you should expect from this boss fight is that each Dark Wizard of Valdis will work together to summon up Xzeihoranth. It will require all of their concentration to both summon and control the beast which gives us a great opportunity to DPS the Dark Wizards. If you can take the damage that Xzeihoranth puts out then I recommend you leave him up and focus on the wizards instead.
After at least one Dark Wizard dies the Xzeihoranth summon will no longer work and the fight against the Dark Wizards will play out much like it did during the Princess Evangeline Story Quest. You're going to want to destroy their crystal shields then DPS them as much as possible while avoiding the AoE attacks that they constantly like to use on the ground.
Mirror Mode will help out a lot when it comes to avoiding the ground AoE. Also it's worth mentioning that when you defeat a Dark Wizard of Valdis the remaining two will heal up to 100% - meaning there is absolutely no point at all for you to split your DPS between them.
With all 3 bosses dead you'll be able to claim the Aegis of Life that is nearby and then return to Lord Kalrathia to complete the quest. Completion of this quest will begin the next one, The Agallan Trial.