Cooling Chamber: Tasnise Underbelly

Quest giver - Rodrick Cleanheart
Requirements - Investigate the Dead and Hunt the Dead
Request phrase: coldain
Entry phrase: willing

Rodrick now realizes that Tasnise is the source of the undead problem in the Cooling Chamber and wants you to find and kill him. After zoning in you will find him in the tunnel. He is a red con, hits for about 10k, immune to snares, can be slowed, and doesn't summon. Start fighting and around 75% he will despawn, blur, and strip all debuffs. At this time the group is ported to the tunnels surrounding the glacier room all the way south. The first step triggers at this point.

In the end rooms in the caves are 5 yellow con nameds. You need to kill them all:

When you loot any of the five gems, the second line updates. Once you have all 5, click any of them to form Dark Gem of the Underbelly and update the third line. Head northwest of the lake near the gate and find Tasnise. Start fighting him there and beat him down to about 70%. Click on the Gem and he will get a full heal, wipe debuffs, but is now killable. If you don't click he will heal every time he reaches 60%. At this point he gains the ability to cast Dark Leeching, Dark Repulsion, and Dark Watchman which summons a pet. Beat him down and kill him, but watch out for roamers. When he is dead the task locks, head back up north to hail Rodrick, and say /return to get ported out. Finally hail Rodrick in the static zone to complete the mission.

The chest contains one of the following: