Move forward and approach Branka, Oghren must be in your party. The path is linear, loot the two Dwarf Corpses and two Darkspawn Corpses as you move on. Check the broken crate and barrel as the Darkspawn horde approaches. Make good use of the Lyrium surrounding you in between waves, by good use that means let the Mages use it. After the waves head down the path looting the two Darkspawn Corpses and three Dwarf Corpses
In the room close the four Gas Valves and defeat the Stone Golems to release the door. Loot the Dwarf Corpse and enter the next room with Blade Traps and more Stone Golems. Use the Lyrium Veins appropriately and march forward for an interesting battle. Kill a Forgotten Spirit where it stands and touch the Anvil behind it to shoot fire into the face and make it spew blood. After a certain time the faces will rotate so kill as many as you can. Hitting the bleeding eyes will stop the Enraged Spirit from being summoned so try to take a side out every time.
Check out the rubble then exit on the west to meet Caridin. Side with Branka or Caridin but know that the other side will attack. Leliana and Wynne strongly disagree and take a huge hit to approval though Zevran, Oghren, and Morrigan will approve. Caridin drops Caridin's Shield and Caridin's Cage while Branka drops Branka's Shield and Vanguard . Either way you can destroy the Anvil of the Void, but choosing to do so is best done only if you sided with Caridin. You will also be crafted the Paragon-Forged Crown regardless of your choice.
Loot the chest for some items plus a Medium Silver Bar . Check the Golem Registry and make an imprint to start the quest " The Golem Registry ". Oghren will ask if you want to go back, you can if you wish but you should go back to Ortan Thaig. Visit the Warrior's Grave here to finish "An Admirable Topsider" and receive Topsider's Honor , a very good main hand Longsword. Return to Orzammar when you're ready.
Destroyed the Anvil of the Void.
Preserved the Anvil of the Void.