Forged Alliance

Read a bunch of posts that were helping a guild who had struggled with this fight -- I HOPE you all have done your homework on it, but here's a brief rundown: Fathomlord + 3 adds (Shaman, Hunter, Priest) -  the shaman has murderous damage output in the form of his spitfire totem and windfury procs.  Raid DPS is going to need to macro /target spitfire and DPS those hard and fast ala the Demoinc Chains on Illhoof.  Then take out the hunter, then take out the priest - then FL. This was the important I thought: Theorycraft time on tanks:

Karathess tank... chances are that the total damage intake on this tank will be the highest. Pally and druid will not have access to thunderclap/demo shout (well demo roar for druid, but still no tclap) until raid starts beating on him... warrior happen to have highest long-term damage mitigation and access to both tclap and demo... his damage eventually are both magical and physical, and warrior also takes magical damage the best... so warrior tank on him.

Priest tank... his damage is like half physical and half magical (warrior takes magical damage better than anyone)... shield bash also helps a lot on interrupting heal... warrior tank on him.

Shammy tank... He is a lvl 71 (?) mob, so he will never crush (unless your tank doesn't have 375 def lol). That negates the only drawback from bear tanking him... he also have extreme burst damage, which is good for a bear to handle. Grounding totem and having raid on him first also reduce most of his damage to physical, and have your dps warrior toss up tclap... So put a bear on him...

Hunter + pet... they hit so light that I have personally tanked him as a holy pally in tanking gears... so put whichever tank leftover on him...


In reality, of course, assuming there's a good amount of gear different between your tanks, then put your best geared tank on shammy add, second best on Karathess, and the rest on priest/hunter adds... 
 

Some thoughts on the Fathom-lord fight from past experiences.  Not sure if the fight has changed since the last time I did it but here goes. Totem killing is extremely important because the totem can and will rip your face off.  The /target spitfire macro is great.  Furthermore, for melee (and possibly ranged) I'm fairly certain that a macro along the lines of /target spitfire
/cast [insert spam ability here, e.g. Sinister Strike] will allow you to spam your normal abilities during the fight by just mashing this macro and automatically target the totem immediately as soon as it is up.  I basically do the same thing for the water elemental totems on the trash on the way to Leo (except it's "/target water" for the first line) and it worked very well in ssc tonight - i managed to do most of the damage to the elemental totems before the elementals had a chance to do anything. The priest can be troublesome.  She occasionally freezes anyone within 10 yards of her which sometimes makes it impossible for your tank to interrupt her heal.  Also, her heal doesn't have a range or LoS checks, so it is imperative that all heals are interrupted.  To counter this we had a lock and a shaman standing by for curse of tongues, the occasional ranged spell lock, and earthshock while dps'ing and healing.  I was asked to do main heal interrupts on my rogue with the warr tank as backup, but it seems like a lock for CoT, shaman for ES and a tank for SB would more than suffice. Tanking positions are important.  Each add has some nasty abilities that can damage or hinder the rest of the raid so it's good to minimize the number of people eating these abilities by spreading out the adds. There are tornados, similar to the tornados in the Wizard of Oz event in Kara, as long as the priest is up.  For the most part they can be avoided.  The worst case scenario I had with the whirlwind was where one hit the all the people on the priest and the priest immediately froze us all before the ranged could back out again which guaranteed a heal by the priest. Healing is possibly the most important part of the fight.  Raid healers need to keep everyone topped off (I think Fathom-lord nukes random people for 50% of their health), and healing needs to be coordinated so that every tank has dedicated heals.  Many different people will be taking lots of damage all at once, and as the fight progresses the Fathom-lord does more damage. The rest of the fight is a DPS race.  Since so many people are taking damage, it's great to have health pots on dps (I think I was using 4 pots per attempt plus healthstones)  Fathomlord enrages after 10 minutes, so you have to burn through 3.5 adds, all totems, and Fathomlord all before he enrages or he will wipe the raid. That's about all I remember from the fight, hope it helps. -Riggins