This is the first of my Dragon Soul guides for 10 man normal mode slanted towards the Demonology Warlock, as the title may have given away.
These are designed to be quick to read (especially the fight rundown as a video guide can explain it far better then I ever could) with specific tips for Demonology Warlocks that you won't find in general guides; What pet? When shouldn't I pop 'Metamorphosis'? Can I stand safely in melee range? What's the best use of 'Demonic Circle'? Does 'Demonic Empowerment' have a use?
So I'll jump right in:
Morchok is a tank and spank fight with 2 very simple mechanics tacked on, he truly is an introductory raid boss.
In phase 1 he does 'Stomp' an AoE which splits its damage between everyone within 25 yards and deals double damage to the 2 closest targets. We stack everyone behind the boss with the off tank slightly closer to make the healing a bit easier but the positioning of everyone isn't overly important beyond being within 25 yards for every stomp.
He also spawns 3 'Resonating Crystals' one after the other that explode after 10 seconds hitting the 3 nearest players for shadow damage that increases the further you are from the crystal and knocking them up. A team of 3 ranged (usually 2 DPS and a healer) handle these crystals stacking on top of them to minimise the damage they deal.
Finally there is a stacking armour debuff for the tanks to swap on. It does drop off in phase 2 (and even after a short string of mitigation) so if your main tank is geared enough it can be easily healed through. We single tank this fight so ignore this debuff altogether and have never had a tank death. If you are single tanking it a feral druid or plate DPS can ideally pop into defensive stance to absorb the double dose of stomp damage but it really isn't necessary. We have our Rogue taking it some weeks and he is yet to die ^^
In phase 2 Morchok drags everyone to him with 'Earthen Vortex' and some stone pillars drop from the sky, 'Black blood of the old gods' then starts to spread on the ground from the boss. This does high shadow damage to anyone caught in it but, to avoid it you simply have to position yourself behind one of the pillars. As long as you aen't standing in the bad there is zero damage in this phase.
If you aren't assigned to the resonating crystals all you have to do is pew pew in this phase, it's a nice fight for Demo warlocks as we can stand in melee range easily.
If your assigned to crystal duty (which you probably will be thanks to shadow ward) then you'll need to break off DPS to stand on them when they spawn. Make sure you stay active while moving to the crystal; pop shadow ward to absorb some of the explosion, grab some mana with life tap, reapply DOTs if you need to and fel fire the boss.
Affectionately known as the 'no damage phase', it's important to note that you can DPS normally while behind the pillars if you position yourself correctly, the easiest way is to head behind 2 pillars close to each other and pew pew between them.
Again make the most of the time you spend running to the pillars: you can grab some mana with life tap if you need it, reapply DOTs or simply fel fire the boss. If I'm heading towards a single pillar I like to hit shadow ward here as well to guarantee I don't take any damage while positioning myself behind it. This phase really does belong in a heroic dungeon, and incidently IS in a heroic dungeon ^^
Your tank should be aiming to keep Morchok roughly where he begins the fight so once you've got yourself into position initially pop your circle down.
The most important time to teleport is at the end of phase 2 so you can get straight back to DPS'ing. Don't worry too much about using it between crystals as you'll either be ignoring them or running to the next one depending on you assignment.
You should open with a blowing of all your short cooldowns as none of the mechanics start right off the bat.
The 2 worst times to have popped meta is right before the phase 2 transition or when your running like a mad man for the crystals. There's not much you can do about the crystals, your either assigned to them or your not and you just have to deal with it. It's best to wait until just after phase 2 has ended before popping meta so you don't get caught out in the phase transition (which has a brief stun and some movement which will ruin your cooldown).
Apart from your opening Demon Soul the Felhunter is recommended. If you are still running Moonwell Chalice then you should still be pet twisting to have a felguard out when you chain your cooldowns.
The fight isn't long enough for 2 Doomguard casts so you can wait for the right moment, remember the Doomguard does NOT benefit from heroism or haste procs but DOES benefit from spellpower and mastery procs.
At 20% health Morchok gets a damage and attack speed buff so expect Heroism then (though the damage buff is so tiny it doesn't really matter, we pop it at the start to catch everyones opening cooldowns) so make sure you have your cooldowns lined up to take advantage of it.