Tasnise Underbelly

Who- Rodrick Cleanheart
Where- Cooling Chamber
Requirements- Hunt the Dead
Phrase- Coldain

Mission steps:

Defeat Tasnise Underbelly - Cooling Chamber
Find a way to defeat Tasnise - Cooling Chamber
The Dark Gem fragment is magical. Discover its secret - Cooling Chamber
Destroy the gem after weaking Tasnise - Cooling Chamber
Kill Tasnise now while he is vulnerable - Cooling Chamber
Talk to Rodrick - Cooling Chamber

Reward:

105 pp
Experience (1 aa)

Notes:

Say Willing to enter the instance.

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

Darkcloth Mummy - In the northwest cave. This one casts Dark Reasoning, a melee slow + snare, and Deathcloth Spore, a dot. When killed it drops a Scuffed Dark Gem Fragment.
Darklight Ghoul - In the southwest cave, This one casts Death's Light as well as summoning a short duration pet. This one also seems to warp to people on agro. When killed it drops a Rough Dark Gem Fragment.
Darksoul Ghost - In the middle south cave. This one casts Deathshock, a whopping 1500 AC debuff and 1200/tick dot. It also casts Dark Reasoning, but seems to have the fewest hp of the five. When killed it drops a Frozen Dark Gem Fragment.
Darkbone Skeleton - In the southeast cave. Casts Dark Leeching, a hefty 16k lifetap and Boneshards, a 20k directional AE. When killed it drops a Smooth Dark Gem Fragment.
Dark Spectre - In the northeast cave. Casts Dark Repulsion, a 14k dd with knockback and Scything Slice a 5k/tick dot. When killed it drops a Jagged Dark Gem Fragment.

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. Once he is dead 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.