<Why must i cry>

External resources for boss tactics.

Hellbreach
    Hellfire Assault
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Iron Reaver
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Kormrok
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube

Halls of Blood
    Hellfire High Council
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Kilrogg Deadeye
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Gorefiend
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube

Bastion of Shadows
    Shadow-Lord Iskar
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Socrethar
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Tyrant Velhari
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube

Destructors Rise
    Fel Lord Zakuun
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Xhul'horac
        Wowhead
        Fatboss on Youtube
        Two Minute Tips on Youtube
    Mannoroth
        Wowhead
        Fatboss on Youtube

The Black Gate
    Archimonde
        Wowhead
        Fatboss on Youtube
                        

Edited: I'm removing info that's no longer relevant to our strategy.

Go kill them imps. Check page 2 of this thread for some visual help to prepare for sunday's raid.
                        

Nice writeup sif =) we'll kill this boss dead this upcoming raid week!

We do need more aoe DPS on the imps, and at the same time more uptime on the big adds.

Look at this comparison of fight logs from our attempt and a clean 5 min attempt that Dunk linked me yesterday:

Our 6% attempt 9m29s
Clean kill 5m18s

You can see that in our logs we had imps up basically all the time while at the same time killing the big add too slow. This might be due to ST switching between many adds (loss of dps) or bad timing of aoe abilities.

The 5min log are getting imps down fast as well as the big add.

What we should try in our next attempt on Xhul is to focus the Big add and max our aoe output on imps as soon as they spawn. This means we would need a little heavier aoe spamming abilities until imps are dead and classes with burst aoe (like hunters barrage) should be saved for the moment imps spawn.

Less switching means more uptime on big add which results in faster phase transitions and less goo on the ground, less movement (less voidfiends) which equals more dps and less messy p3.
                        

Okay guys, tomorrow we're gonna kill this jolly old fellow, no excuses! FOR THE QUEEN
                        

Hide this picture of shame. I am not even at the top 3 DPS.
                        

RETREAT! RETREAT!

Alright, but on serious note. I took up to watching the mythic kill videos of this fight and there seem to be a few elements we should adopt into our play.

1st.
In their mythic kill Method had felsurged/voidsurged players stack up, leaving all the patches in one spot effectively saving space and making it easier to clear. They also dropped new patches on top of the old ones by stepping in the fire as the next one was about to fall off. This means a bit more damage taken, but so much less space used.

2nd.
As the imps spawn in the close proximity to Xhul'horac, he was tanked very close to the middle and had no tank movement. I don't think we should do this since it requires quick response from the debuffed players to move out in the same spot. Additionally learning a completely new way to do the fight would most likely be less effective than just adopting one element of it. 
However I do think that we should instead of constantly dragging the boss, just attempt to tank him still on the green side during phase 1 and have 2 spots (markers) directly under which the patches should be dropped. (If I understood correctly, the patches leave behind a ground effect which doesn't stack (increase the damage output) even if the areas are overlapped. If however this turns out not to be the case, the patches could be simply dropped along the edge of the platform as we are doing in our current strategy, except with the affected players stacking up.) On p2 we could do the same on purple side. This would mean that the markers are constantly open for clearing and the whole raid doesn't need to move. In p3 and p4 boss could then be tanked in the middle and fel-/voidsurged players should continue dropping the patches (preferably stacked) on respective markers from p1 and p2. Hopefully this would mean that the center stays clear the whole fight (provided that we don't fuck up with the adds)

I suggest that we at least implement 1st point to our strategy to down this bastard. It should improve the melee's freedom to reach the spawned adds.

(Some sources also say that the damage taken for big add and Xhul'horac would is shared. Eg. when Vanguard dies, Xhul'horac is always on 65% health and phase 3 beging. Omnus is summoned at 60% boss HP and we have never had these adds overlap. If this is true, cleaving boss and Vanguard/Omnus together should push us to p3 faster and would also mean that dps can focus one target that suits them better in the situations where boss and add are apart.)
                        

I just happened to watch some logs, and saw the fastest kill on HC :)
CLICK THIS OMG UMAD?

Go to replay and see how they position themself, i know they have better gear but this should be doable ;)
also that they have assigned 2 ranged for the voids. 1 hunter 1 druid that keeps moving from site to site.
                        

http://i.imgur.com/Sku5lh1.jpg new tacs npnp
                        

Sif, we will try a tactic like this :) I talked to Dimacharka yesterday who proposed a different strategy that seems so much better (in theory) than the one we've been trying so far.

Explanation for the screenshot of the markers i posted earlier:

Skull: tanks + boss + big add (staying here in all phases, stationary, less movement, more focusing on taunting and better add control and more cleave)

Red marker: DPS (melee dps stay max range so we can have all grouped up together for faster small add kills and shorter way to the surge drop locations)

Green marker: Fel surge
Purple marker: Void surge

Now we should start off trying what you said method did, sif, and make the green areas smaller by dropping it tighter into already affected spots. But still, having the areas this close and compact our rogues should have no trouble clearing it fast before it grows big.

Also we had trouble with voids in almost every attempt, so we should try like Dunk posted now, to have 1 or 2 kiters for voids who can also focus them down, between imps.

This in total would result in way less movement = more uptime dps combined with more cleave dps. People also have to worry less about moving which means more focus on adds (imps especially) and also we should be able to get the vortext at the furthest away players (i think) so it will be more predictable.
                        

From the videos i have seen it still looks like ominus ( the other miniboss ) is spawning void surge the moment he spawns, so the stand still not move tactic might not work because of this.

Anyway i suggested this tactic instead of fatboss, as i quote "The fatboss strategy kind of stinks and leads to a lot of fire everywhere. Here's how we do it" Taken from reddit.

Click Click
                        

I checked Dunk's link here and did some elementary level math. With their raid comp boss had about 275m hp in the beginning and Vanguard spawned at 90% with 66m hp and died at 65%. the 0.25x275m = 68.75m. Same thing with Omnus spawning at 60% hp and dying at 35% hp. Even though this throws off by 2m I think that the rumors of boss and the big add sharing health pools is true and we could take advantage over that.
                        

Quh make a Quote thingy! :D

Yeah Sif i think your absolutely right :P
                        

This is good information :)

Also from wowhead: "Damage dealt to Vanguard Akkelion will be copied to Xhul'horac, and damage dealt to Xhul'horac will be copied to Vanguard Akkelion." Same thing with Omnus.

Also dima's tactic, like you say dunk, does not take omnus spawning crap int account and would require a moving of the boss before omnus spawns. But, are you sure that Omnus actually spawns creeping void? I have been looking but cannot find it. Are you sure that the void crap is not spawned from players getting hit by the voidfiends that spawns before omnus?

And yes i will make a quote thingy :D:D
                        

Well me and tsumeato was watching some videos yesterday, and all the players with void surge moved to the edge, and when the ominus spawned there was some crap :P we will see sunday when we try out dimas brainiac tac :P

AND THANKS! :D