The Gate Captain has many enchanter arts and is likely to attempt to mesmerize, stifle and stun you frequently.
Follow the ledge west then north, slaying any yetis along the way. You'll come to a large chasm--take a sharp turn left (west) here.
Tamer Nicoli is in the southeastern corner this area. Slay him and his two yeti friends.
The Tamer has a tendency to attempt to pin, stifle and stun you often, making it a fairly difficult fight for some. You may find it easier to quickly kill the two tamed yetis before focusing on Nicoli.
Continue west and turn south at the chasm. There is an opening to a tower to the west--jump over the narrowest part of the chasm here to reach it.
Pick up the glowing plank at 99,-0.26,-89 . Jump back over the chasm with it and head toward the eastern tower.
The chasm to the eastern tower is larger than the one over to the western tower. Place your plank as close to the edge as you can around -41,0.63,-81 . Run across the plank and leap across.
Kill the Construct and Guardian inside. There is a plank here at -96,1,-83 , which we suggest moving to the bottom floor of the western tower now.
At the top of the eastern tower is Kastus. You MUST kill him before you can progress to the last two nameds.
Do NOT use spells against him! He will reflect damage back to you if you try.
Combat arts and melee weapons are fine to use.
After slaying Kastus, grab the plank at -85,26,-70 and take it over to the western tower. Also remember to go back and grab the plank you bridged the gap with by the eastern tower and take it back!
At the top of the ramp in the western tower is a summoned barrier of ice. Click on it to target it and attack the barrier until it is destroy. At lower levels this can prove to be difficult as the wall will regenerate more quickly.
After slaying the Ice Maiden past the barrier, equip the weapon you received upon completing Mission Improbable....
She will randomly pop up adds during this fight. We recommend killing the adds quickly as soon as they come up, otherwise they can quickly overwhelm you.
Break the dragon egg down near where you first saw Ice Maiden D'Ina standing. ( -63,-46,-308 )
Players who are on the quest Covering Your Snow Tracks! can depart without doing this step as long as their quest has already been completed, and assuming that they have an ability to take them to the entrance, such as Escape.
After you thaw out (about 1 minute wait time), grab the shell of the egg and Snarf will run in. You can speak with him to complete the quest It's Time to Sleigh the Dragon! as well as leave the keep.