From Sage Daelun's "Chronicles of Antediluvia", volume XVIII:
 Episode I: The Fall of the Shadow-King 
 Episodes II & III: The History of the Great Wars  
 Episodes IV-VI: The Rise of the Imperium  
 Episode VII: The Quest for the Trinity of Might 
 Episode VIII: And Lo, When The Imperium Marches Against Gul-Kothoth, Then Dark Sorceries Shall Enshroud The Citadel Of The Obsidian Crown  (recounted on the second Bal-Sagoth album; "Starfire Burning Upon The Ice-Veiled Throne Of Ultima Thule)
 Episode IX: The Obsidian Crown Unbound (The Legions of the Imperium Storm the Cloud-Capped Palisades of Gul-Kothoth)
(here recounted on the sixth Bal-Sagoth album; "The Chthonic Chronicles") 
 Episode X: The Shadow-King Reborn
 Episode XI: The Battle of the Nine Armies (The War of the Crown)
 Episode XII: The Great Rebellions and the Dissolution of the Imperium
   

The Obsidian Crown Unbound (The Legions of the Imperium Storm the Cloud-Capped Palisades of Gul-Kothoth)

Chapter 11: The Siege Begins 

And so the mighty and resplendent armies of the Imperium assembled before the towering cyclopean walls of ancient Gul-Kothoth. It was some time before the billowing dust cloud raised by the massed arrival of the vast imperial host settled, ultimately dissipating as the shadows of dusk descended. With nightfall, the imperial army's countless torches, braziers and cookfires illumined the dark plain before the fortress like a [bad word] sea, painting the stygian heavens the colour of flame. And the high summer's night passed swiftly. At length, the dawn approached tentatively, and with the first signs of the newborn sun etching its promise upon the skies, the martial [bad word] in earnest. brief and perfunctory exchange between the Imperial Herald and the fortification's [bad word] held no surprises, and the Emperor's banner was duly driven into the seared earth before Gul-Kothoth with a chilling finality. Vast siege engines and powerful ballistae were hauled inexorably into position, alongside a battery of katapelte and petrobolos. The one hundred thousand strong Imperial Frontier Army, having planted their regimental blazons into the arid soil, waited with a disciplined patience born of never having met defeat in pitched battle or siege, the dreaded Imperial War-Leopards straining noisily against their iron-link leashes to the rear of the cohorts of conscripts and auxillieries. The pitiless Iron Phalanx and their Lord [bad word] had assumed position at the head of the army's Alpha Wing, polished swords, spears and poll-axes reflecting the glow from the myriad torches and braziers which still burned about the Imperial Host. And behind them were drawn up the legendary Legion of the Ebon Tiger, Pride of the Emperor, the infantry and cavalry famed throughout the Great Northern Continent, personal regiment of the feared general Baalthus Vane. [bad word] to their martial reputation, the six thousand strong Legion were [bad word] in their jet black armour, their sable banner billowing in the chill breeze which skittered over the plain. And finally, astride his azure-shaffroned warhorse and surrounded by his elite guard, the silvern-armoured Emperor Koord himself studied the precipitious gates with a disdainful [bad word]  At the Emperor's right hand was the renowned Swordmaster of Kyrman'ku, an eastern bladesman of preternatural skill and the most revered and expensive mercenary in the Imperium. At his left, the infamous Ogre-Mage of the Black Lake brooded silently, swathed in a stygian cloak and fuliginous cowl and exuding an aura of implacable malevolence which unerved even the bravest of the Imperial troops. The Emperor had deemed the services of these two nefarious renegades pivotal to the execution of the Final Campaign, for they alone had knowledge of the mysterious arcane rite known as The Words Which Unfetter. 
 And, behind their titanic time-worn palisades, the defenders of Gul-Kothoth beheld this awesome

We march to war - The Siege Begins

0:41
Pride of the Empire
the Ebon Tigers of bloody claws
???--???Iron Phalanx  (0:46-0:49)
Our victory here is assured

1:12
(The Emperor Koord:)
You should not call your falcons before the hunt is done, ??silver crown?? ...?? (1:16-1:21)
Raze Gul-Kothoth to the ground!

1:28 / 1:42
(The Imperial War-Skalds:)
An age of fire, sword and shield
The thunder of the battlefield
The clarions call, bring down the wall!
May the Empire's glory never fade
Righteous fury guide our blades
We march to war!
X2

1:55
(The Wizards of Vyrgothia:)
Darkly bejeweled circlet of night, Crown of the Elder King
Unfettered at last the Trinity of Might, the Sceptre, the Sword and the Ring!

2:08
(Chapter 12: The Fall of Gul-Kothoth)

2:21
(The Sorcerer:)
And upon that arid field of war, the sentinels of light and shadow spoke to each other in tongues dormant since the Third Moon fell burning from the heavens, and not sweet were the words they uttered

2:47 amazing riff

3:15
(The Imperial War-Skalds:)
Sundered the gate of the ancient fortress
Besieged! Now breached stand the walls
And lo, there an army of five score and ten
Behold! The Obsidian Crown
Embattled, the wizards, their weapons arcane
Untramelled, the circlet, the Prime-Sorcerer slain
The Crown's peerless power, the Emperor's bane
Dark magicks and havoc, now red carnage reigns!

4:22
(Baalthus Vane:)
By all the gods of war!
Stand fast, hounds of the Imperium!
Glory to the Emperor!
Into the foe!
Show them the Tiger's claws!

4:33 (vicious riff)

4:51
(The Emperor Koord:)
I call thee forth, Ogre Mage of the Black Lake!
I call thee forth, Swordmaster of Kyrman'ku!
It is time!
Now, I charge thee, 
Speak the Words Which Unfetter!

5:45
???crown??? (5:45-5:57)