The Wight Specter is the first named you'll encounter, surrounded by surging wights. If you range pull any of the surging wights, it will aggro all of them and the named. You can proximity pull the individual groups if necessary. Killing the Wight Spectre will cause the other named in the dungeon to spawn. Note the surging wights will frequently stifle.
Ecto Malgum will periodically summon apparitions during the fight and can disarm the tank. It's recommended that you clear the surging wights around him, because all of them in the area will attack when he is pulled. A good place to fight him is in the cave at ( 5, 8, -76 ) Copy/waypoint 4.70, 8.10, -75.60 to avoid the summoned apparitions.
Crystasha is a named spider in the next hallway. She is preceded by five waves of deep widow spiders. She has a poison attack called Necrotic Venom and an arcane attack called Vengeful Terror.
In the next area, The Fractured Altar, there is Judithaina, Lilithiana and Secratiata. Clear the room of all other Ca'Na near them, pulling them back into the cave. They can knockback, so avoid fighting them out in the open. When fighting them, try to keep their health close to one another, switching targets as one gets lower in health. When they are all down to about 5% health, kill each of them as quickly as possible.
Cross the bridge to the Pools of Venom where there are vipers in the water, along with Kraitenae and her three snakes, Nuratoxia, Tetroxae and Hemotoxia. Clear the vipers, then focus on her snakes first, starting with Nuratoxia. Once they are dead, she can be killed. Fight them where she stands. This is a very cure-intensive fight. Kraitenae will taunt the tank off her snakes and has a knockback. There are more Ca'Na just beyond her cave, so be careful with positioning and don't get knocked into them.
A Ca'Na Soulmistress is a bonus named which drops an Exquisite chest. Like keys mobs, she will cast Mandate on her target. If you are alone in this instance, you should have a healer mercenary with you unless you can kill her very quickly.
Queen Gwarthlea is the final boss of the instance. Clear the Ca'Na elitia near the ramp and around the pool. It's recommended you pull them back into the cave hallway because they do knockback. Then go to the pool and clear the rest of the Ca'Na while inside the pool. See her strategy page for more specific information on fighting Gwarthlea.