Look at this big bastard;
http://i49.tinypic.com/wtegbs.jpg
That's a
castle he's standing on. In other words, he's a big mama-jama. The fight is pretty much going to have to go like this;
(Warning: Long.)
TLR version: Learn to read. What are you, six?
Setup:
Grim Batol's wings each have massive seige engines, an army of dragons, and lots of resistant magic. Players must clear all of these defenses to make way for Alexstrasza and a multi-colored army of dragons, who swoop in and head straight for Deathwing.
Phase 1: Clash of the Aspects
Approximate time: 3-6 minutes
Players enter the heart of Grim Batol, finding Deathwing coiled in the central forge chamber (think Ironforge). Alexstrasza and the dragons engage him, which is a fight that doesn't go very well at all. On the ground, players must protect fallen dragons from adds while healer NPCs rush in to heal them (Players can also heal, allowing the dragons to get back up faster). Players don't actually fight Deathwing during this phase, they just need to survive and keep enough dragons up to DPS him to phase 2.
I'm talking sheer anarchy, dragons getting thrown around and smashing the entire hall to pieces, with rocks falling everywhere, buildings collapsing, lava splattering everywhere; total chaos with the players just trying to survive and keep the dragons up. Phase 1 fails if the raid wipes (adds overpower or they eat too many rocks/lava spurts) or all of the dragons die.
Adds may be left alive during this phase, resulting in a Phase 4 Hardmode.
Phase 2: Skyward
Approximate time: 1.5 minutes
Alexstrasza calls a retreat, and the remaining dragons flee upwards through a hole in the chamber's roof. Granted a speed buff, players hop onto their flying mounts (temporary drake mounts are available if needed) and the raid soars upwards at break-neck pace (they automatically climb upwards, but players can move around horizontally). Below, Deathwing erupts (literally) through the ground behind them, and fires off several blasts of lava as he tries to dig himself out. Every 20 seconds, three enormous balls of flame rocket past the players, who need to avoid them or wipe; their paths are kind of clearly marked and players can avoid them fairly easily. Players need only survive to complete Phase 2; this is a fairly easy part.
Phase 3: Exposure
Approximate time: 5-10 minutes
Catching up with Alexstrasza, the entire raid lands on her and Korialstrasz' (Krasus) back as they continue a nearly vertical ascent. Deathwing catches up and begins to sweep between the two dragons. During this phase, he will fire lava at one dragon, knocking them out of the sky. The players must jump down to the other, who swoops in to catch them. Players who fall are caught by drakes, and are forced to ride the rest of the fight (though a few players on drakes are needed).
During one of his passes, the players are told to jump onto Deathwing and start destroying his armor. They land on the beast, but must weather a damage aura (from the heat) and maintain their grip (similar to the Hodir daily) as Deathwing tries to shake them off. During this time they are to DPS four plates on Deathwing's belly, but as each plate eventually falls away, huge plumes of magma flow out from the wound; players need to avoid these spurting plumes while continuing to DPS his armor pieces away.
During this phase, a few players riding on drakes need to stay close and use their breath attack to deflect these plumes away from the players (because eventually there are three open wounds, too many to dodge). When the last plate is nearly broken (Alexstrasa calls out when it's time), the players must mount up (or call in a drake if they need one) and fly off.
Phase 4: Northrend
Approximate time: 3-6 minutes
The dragons have lead Deathwing to the ceiling of the world; Northrend. Alexstrasa claws at the last plate, digging into Deathwing's body and crushing his vitals. In agony, the dragon crashes down into the mountains around Icecrown Citadel, where his heat causes a steam to cover the landscape. Players land near the fallen Alexstrasa, who is severely injured, and a plan is put into motion; Deathwing must be impaled with a sliver of the Frozen Throne, the only substance that could possibly injure him.
Deathwing bursts through the fog, knocks Alexstrasa into a chasm below, and sets about destroying the raid. Injured, the dragon can barely walk; tanks must keep him occupied while DPS focuses on keeping him immobilized by DPSing his legs and wings simultaneously. All the while, dragons are swooping in and blasting him, which occasionally causes him to collapse (giving players a chance to deal with any adds on Hard mode or rest up quickly). If either DPS team fails, he gets back up for a bit and rampages around until the drakes are able to subdue him (though it's pretty likely he'll wipe the raid).
As a hard mode option, enemy dragons may show up during this phase, which must be tanked separately and DPSed during Deathwing's collapses.
Once sufficiently injured, Korialstrasz swoops in with a chunk of the Frozen Throne. Rolling to protect his wound, Deathwing prepares to blast the dragon as he decends. At the last moment, Alexstrasa pulls herself up onto the cliff and fires a shot into Deathwing, exposing his wounds just as her consort plunges the shard into Deathwing's body.
Phase 5: Rupture
Approximate time: 3-6 minutes
In this phase, Deathwing begins to fall apart (leaving spurts of lava that must be avoided) while the players attempt to keep him under control (lest he wipe the entire raid). He must be tanked as in Phase 4, with the DPS focusing on his limbs to keep him from lifting off or running about. The added challenge comes from the fact that Deathwing, being torn apart from the inside, is causing the cliff side to crumble around him. Parts of the land slide away, and players must move off these crumbling pieces before they fall, forcing them to get closer and closer to Deathwing. During this time, the dragons continue to blast him, bringing his health down further until he dies.
Once he reaches zero DPS, a FMV is shown of the dragons rescuing the raid as the mountainside collapses around Deathwing and he falls, turning nearly into stone, and shattering at the bottom of the canyon (which becomes phased for those players, showing a few limbs and claws sticking up from the rubble). Alexstrasa lies nearby, and commends the players for their bravery before passing on. Korialstrasz lands nearby, and offers players their reward.
The reason most of the DPS on Deathwing comes from NPCs is simple; it keeps the raid moving along at a fairly fast clip, from one event to another, with the players basically keeping Deathwing occupied. It's also a LoLore thing; he's powerful. If the players could kill him, what kind of a monstrous demigod would be be? Instead, the players have to try their hardest just to keep him under control, while the dragons do all the work.