The Tempest Reaver Is part of the New Jaggedpine Quests... The Essence of the Tempest Reaver is for a WAR/PAL of KARANA Only Quest... The Quest starts from Lady Deria(spelling?) In Jaggedpine at the fort. The will (if you have high enough faction) tell you about the Tempest Guard, and Ask you to retrieve 2 things, First is a diary/Journal from Neria The Beguiled, in Kedge Keep, and the 2nd is Crown of the Underfoot from TziTzi the Crazed in the Hole.
When you give her these she will take them and give you a Book to take to Lord Mallron in South Qeynos at the Temple of Thunder. He will in turn ask you to retrieve a Rune of the Tempest, Which is found from a named madman in South ro (Not sure of Name) And the Essence of the Tempest Guard, from The Tempest Reaver in PoF... You take him the rune, and he will hollow it out, There after, you put in the essence and Hit Combine, Giving you a Rune of the Tempest (after)
You take the Rune and crown to Lady Deria again, and she sets the rune in the crown awarding you with a Crown of the Tempest Guard, War/Pal of Karana only, 26 ac, 10 sta, 5 str, 5 wis, Effect Is a Damage Shield (stats could be wrong, but are4 pretty close)
I don't remember how tough he was with a raid force, but I went to Fear the other night with a 60 Necro friend. (We are both level 60 Necros)
It's true he's immune to Slow, snare, root, mez. I didn't get the message that he was immune to fear though. (He did however resist it the three times I tried to land it.)
He only hits 149ish, but can outrun Jboots. (I pulled up a Spectre pet with the Hate focus book that makes your pet run at JBoot speed and he NEVER was able to catch up to the Reaver no matter how many times I circled.)
SoW can outrun him, but if you sneeze or try to stop long enough to feign he's right on top of you.
The two of us did manage to kill him out of a matter of principle after about 10-15 minutes of aggro kiting.
In addition to not being mezzable or stunnable, he is not slowable and will devour a 60 tank with 5k hp in short order. Don't let this one aggro on anything other than the MA if you want to live.
Level 56 shaman, tried Plague of Insects (PoI) first because I guessed he might be extra resistant and got the message that he was Immune to changes in attack speed.
Wasn't hard at all, dropped essence of the Tempest as well.
Taladaen Shaman of 56 winters - Rip Tide Solusek Ro
Only has one drop. Essence of the Tempest. Is a War/Pal item No stats karana followers only. Similar mob to the one in Plane of Hate. Is NOT stunable or Mezzable.