So I was horribly bored and decided to do this.
Note: I will not be adding anything like x damage or a debuff that lasts x seconds. Im not a Blizzard designer that knows how to balance this. Im neither someone who knows the lore inside out, so if I missed out on something in the lore that causes anomalies in the story, Im sorry. Post them in a constructive manner and I might edit the story. I never wrote a story before, so please don't flame right away. (Ps, my apostrophe button bugs out half of the time, I cant do anything about that either)
Also, the fight as you might notice contains Hellscream. It's up to you if you read that as <insert Alliance hero> if youre Alliance or just accept the fact Horde and alliance have to work together this time.
Things you should know about before reading on:
The Demon Soul in an artifact created by Deathwing, and empowered by every Dragon Aspect except Deathwing (however, the others didnt know this). They empowered it under the belief that the Dragon Soul, or now the Demon Soul, would be used to wipe out the Burning Legion. Rhonin later destroyed the Demon Soul, causing the other aspects to regain their power and defeat (but not kill) Deathwing.
Neltharion the Earth-Warder is the same person/dragon as Deathwing. The Old Gods turned him insane.
Nozdormu the Timeless One is the Aspect of Time and has control over the past, current and future time. This will play a big part in the fight.
Ysera is the Dreamer, which allows her to enter the minds of others, and manipulate them in either the form of dreams or nightmares.
Alexstrasza is the Life-Binder. She made a promise to Rhonin in Day of the Dragon, promising she would never harm the ones that saved her.
Location & Start of the fight
Alextrasza, Neltharion.. He's wreaking havoc on the lands of Azeroth more and more. This has to be stopped!.
Neltharion, or Deathwing, has destroyed Azeroth. The majority of Azeroths population has been wiped out, with only those hidden away or able to protect themselves from the all-destroying flames of Deathwing still alive. The Aspects Alexstrasza, Nozdormu and Ysera, together with Korialstrasz, are watching Thrall leading the players to Grim Batol, luring Deathwing to them at the same place Alexstrasza and Deathwing have fought before, to defeat him. Nozdorumu doesnt want to get involved at first, but gets persuaded by Alexstrasza and Ysera to help the players out.
..Seconds before Deathwing finishes casting his all-destroying flames on the groups of players, the Aspects empower Thrall for a moment allow him to ground the spell away entirely...
Deathwing: What..?! No! Impossible!
Alexstrasza: You are not alone, mortals. We can no longer see Deathwing destroy all we lived for!
..Ysera enters the mind of Deathwing, paralyzing him in an state of nightmares about his past activitiies. Nozdormu sends the players, Thrall and Alexstrasza back just hours before Deathwing destroyed almost all life on Azeroth, flying just above Orgrimmar.
The Fight itself:
Thrall: We have to hurry, heroes! We do not have much time before Deathwing will be able to get away and destroy all living being on Azeroth!
Forfilling her promise, Alexstraza orders her kin to pick up the players and Thrall, who chase after Deathwing. Rhonin, still empowered by the Aspects, casts a spell that temporarily causes Deathwing to slow down, catching his attention.
Deathwing: Ha! You tiny mortals honestly believe you have a chance against The Unmaker of Worlds? I said it once and will again: Have you not been through enough? Will you continue to fight what you cannot defeat? You stand no chance!
The players catch up with Deathwing, who is hovering in the air, cackling at the players. The airs turns red, with shadow covering the whole area of Orgrimmar. A massive explosion ensues after Deathwing finishes casting his spell. Nothing but a crater is left of Orgrimmar, and the players are utterly destroyed.
Nozdormu: Neltharion! You have turned the wrong way! The Old Gods corrupted you too much, there will be no turning back!
...Nozdormu casts a spell that turns time back a few seconds, causing Orgrimmar and the players to live again...
Deathwing: What? Nozdorumu? So.. much.. power! Thats not possible!
Nozdormu: Don't you remember? You, who once tricked us to give you our power by empowering the Dragon Soul? Alexstrasza and Ysera have given me their power, risking their own lives for it in the future timelines! You have found your equal now, Neltharion!
Nozdormu: Mortals, strike now!
..Nozdormu casts Sands of Time on Deathwing, causing Deathwing to grow older.. Weeks, months, years of fight without rest go past for Deathwing, allowing the players to get close without Deathwing being able to react in time..
(Garrosh Hellscream, who had been sighting the fight from below, joins the players and encourages them to jump on Deathwings elementium scales.)
Hellscream: We will pin his head on the very same place as others of his own kin like before, heroes! We must find a way to get rid of his scales, so the dragon is no longer invulnerable!
At this time, the players will get buffed by Thrall and Korialstrasz (on who Thrall has been riding, and who now turned back to his human form as Krasus) to make up a bit for the immense power differences between Deathwing and the players. The players must damage certain elementium plates, with each defeated plate causing Deathwing to gain extra damage, but also spawning adds that the players have to defeat. In the meanwhile all kind of races Deathwing has corrupted are trying to defeat the players, both on his body and from air. The players have to divide damage, healing and tanking to take care of everything. Every once in a while a player will get picked up by a twilight drake and gets dragged towards the mouth of Deathwing. The players have to damage the drake while the picked up player has a special actionbar that allows him to slow the drake. All this happens while Deathwing keeps flying around Kalimdor.
(The first plate falls off. The raid can choose which plate they take, causing different buffs or debuff on the players or Deathwing depending on the location of the plate)
Hellscream: That will be his weakness! Strike there, now!
Garrosh Hellscream and the players should now attack the place where a plate was before. Each hit dealt to the plate will cause that player to get a stacking debuff with damage over time, 'Burning Hot' that can be removed by jumping on the Crimson drakes that are flying next to Deathwing. While on this Drake you can control him to place either buffs on players, damage Deathwing, heal players or cause special effects like slowing the flying adds, causing them to fall behind Deathwing and no longer being able to catch up.
Each time a plate falls off after the first one, Deathwing will roar in pain, causing the raid to fall off. The players have to react before this happens by jumping on the drakes. There will only be enough drakes for 80% of the raid. The rest of the players have to hook themselves to Deathwings body, causing immense amounts of damage. The only way to survive this is to use the abilities of the red drakes similiar to Pain Supression and normal heals.
After 5 plates have fallen off Deathwing will receive +50% damage on the weakened spots. The raid has to nuke down Deathwing to 50% before they get overwhelmed by adds now. when Deathwing reaches 50%, a new phase makes its appearance.
Deathwing: Enough of this! You shall feel the wrath of the Destroyer of Worlds now!
(Deathwing dives towards Feralas, landing in such manner that the raids falls off. He sweeps away Thrall, who seems to be crushed against a mountain wall. Garrosh, who is still under the buffs of Krasus and Thrall as well as getting heals from Krasus will be tanking Deathwing. The healers must keep him alive as well as the tanks and dps, who will be encountering several things:
-Adds: Twilight Drakes, corrupted Drakonids and more will be spawned by a portal that Deathwing conjures, which looks similiar to a gate conjured by the Pantheon, but less powerful.
-Crumbling/falling stones: Deathwing will use his power of the Earth to shatter and lift all ruins as well as what remains of Diremaul to throw at the enemy, compareable to the last boss in the Stonecore. Players have to avoid this.
-Corrupting Minds: Deathwing will occasionally corrupt players the same way as he got corrupted himself, promising big powers if they help him out. These players have to be weakened by the rest of the raid so Nozdormu can lift the corruption by whispering soft words and trying to reverse time on the player.
-Other abilities: Deathwing will have the normal Dragon abilities (tail sweep, flames etc) as well as an air phase and a stacking debuff that requires tank swapping as well as melee running out back and forth: every 2 seconds near the molten body of Deathwing will cause the player to gain a debuff that doubles each new stack, causing damage and movement slows.
Airphase:
At 50%, 40%, 30% and 20%, Deathwing will lift off. At this time the drakes (who have been damaging Deathwing from air all the time) will lower, causing some players to be able to jump on. These players must use chains to hook on the spots in Deathwings body from which plates have been removed already. If enough chains are hooked, Deathwing will shake them off but also land again.
After Deathwing hits 10%, player-wise he has been defeated. A real-time cinematic happens:
Deathwing: I seem to have underestimated you, Nozdormu, but that has only delayed your demise!
Nozdormu (realizing the power Deathwing is about to unleash): Mortals, take Alexstraszas drakes and get out of here! I will use the remaining bits of the power of us 3 aspects combined to finish this once and for all!
Deathwing: There will be no where to flee after I am done with you, Nozdormu!
Nozdormu: You seem to forget one thing, Earth-Warder.. I am the Timeless-one, I know how this will end, once and for all!
The raid jumps on the drakes which cant be controlled this time. The players fly above Deathwing, who is now channeling a lightening-bolt similiar to the one in Day of the Dragon, aiming for Nozdormu. The moment he releases his magic, Nozdormu uses his power over the Time to slow down the beam, trying to make it go backwards in time and exploding in Deathwings proximity. At this time Garrosh Hellscream jumps off his drake, landing on Deathwings back, and striking a blow in the open spot created by the raid at his neck. Dazed by the mighty blow, he loses his concentration and causes Nozdormu to be able to send back the beam, which then explodes at Deathwing himself, who falls to the ground. Garrosh, however, is no where to be seen.
(Nozdormu casts a spell again, sending back the raid, Thrall and Krasus back to the time they left before).
Nozdormu: Alexstrasza, Ysera! Deathwing is no more! These mortals have succeeded!
Alexstrasza: Then I must thank you, mortals. This will be a day to never forget: the day that Deathwing perished! Ysera had been able to keep Deathwing paralyzed in this timeline, but after channeling her powers to you she couldnt hold Deathwing anymore. These mortals were just in time finishing him off! I must go now, Ysera will need my help. Ill help her get back to the Dream, where she can rest...
Thrall (to Nozdormu): Timeless One, what has become of Garrosh? We have not seen him since Deathwings demise!.
Nozdormu: Do not worry, wizard. Do not worry.. Time will tell what has happened to him.
(Krasus teleports the raid to their original city, where they will be awarded with their loot.)