Ok Guys, here is the REAL way on how to go about killing Yakhmar (Level 80 Raid Boss). This is very similar to the way that you kill Kyllikki, using a circle AoE and getting under the raid boss. For this, we used 4 casters and it took 1 1/2 hours, so I suggest 6. I'll be posting screens later on how to get down under Yakhmar, but I'll tell the strat. You will need a ToS specced for totems and cyclones for this otherwise Yakhmar will just reset off of the bat. The designated ToS(s) will need to throw their cyclones and totems right next to Yakhmar... this will give Yakhmar a target to path to so that he doesn't bug out. These totems and cyclones need to be up at all times or you just wasted progress. Once the totems and cyclones are up, you need to use a circular AoE (Deathly Blizzard, etc., etc.) on Yakhmar's head. That is it, just sit there and spam away =P.
Important Note: Those of us that did this used AoCBuddy, allowing us to easily get down under the ground and use the Max Zoom Out Feature, but there is a way to still get underground without AoC buddy, but you need a ToS to self rezz and someone above ground and way away from Yakhmar to do this, I'll post screens later like I said. Yakhmar will spawn a ton of minions, don't worry about killing them, he'll just spawn more. When we all got done with Yakhmar, we had roughly 4-6 FPS =P. Now, if you do this the AoC buddy way, the ToS needs to move above ground (Alt + page up by default) and letting the minions kill him with their AoE stun. Make sure though that you kill the minions on top of the chest if they can be. When the ToS is killed, he will need to self rezz. When he self rezzes, he will have that Shield on him and Voila, no longer stunned and can loot the chest.
Doing this without AoCBuddy way is the same concept, having that person above ground and away from Yakhmar do the same thing as above and self rezzing. Give me some time to put screens together. Still wish the "Leash" spot worked. Sorry if this is not so clear, PM me for help and assistance.
Have fun =)
EDIT: Well, this is gay. It seems over the weekend when I was gone they patched the fall through spot =/, so it looks like the only way to do this is with AoCBuddy >.<. Anyways, here is screens =/. Sorry about this guys.
EDIT #2: Looks like if you don't want to pay $50 for AoCBuddy (Mine was free XP), somewhere along this forum is the AoCDebug which is basically the same thing, so I just pretty much gave a strat =/. Again, sorry guys.