After that, 2 and 2 more piles spawn on the overlook area and needs destruction. Two bone piles will spawn first, then 2 more, and finally 1 last bone pile on the bottom. One possible way to deal with this is to leave the ranged DPS on the overlook to handle the bone piles spawning there, and keep the healer and tank downstairs. Using the lever starts the fight and close the gates. Past door 2: There is a room with many inactive spike traps, an incantation stone and a lever. To the left is a bone pile that also needs destruction for the challenge. During the first fight, it will spawn 4 bone piles there).
The area between door 1 and 2: This part has spike traps, 1 trap mechanism, 1 strange rune to the right, which lets you locate a suspicious wall (which requires a guardian, warden, or champion leads up to an overlook of the first fight room which is past door 2, and on this overlook there is 1 trap mechanism. However, he will not take damage from any source.
He will follow you as you progress in the instance, but will stop if any mob aggro on him and will require coaxing to continue. He will enable you to operate the riddle doors. Get down in basement and open the suspicious bookcase, and head down to Umín.