Galen, a master of procrastination in his personal affairs, transformed into a whirlwind of action when it came to strategic planning. Even as the armies of Stormwind and Gilneas were still assembling and the fleets of Kul Tiras and Stromgarde remained in port following the Dalaran mobilization, Galen had already amassed a formidable air force of eight thousand aircraft in Sholazar Basin, poised to strike the cliffs of the Avalanche Mountains.
The pilots of this aerial armada comprised three thousand gnomes and five thousand retrained farmers from the Heart of Origin. An additional fifteen thousand such pilots were stationed at Eastwind Rest. Notably, the first generation of Heart of Origin units had begun reaching adulthood, exhibiting an innate intelligence surpassing that of their parents and even ordinary Azerothian humans. Galen dedicated himself to their development, with some choosing to become pilots and tank crew, while others displayed a talent for military strategy. After training at the Paladin Training Camp, these promising individuals were integrated into various main battle legions, earmarked for rapid advancement to legion command.
Eight thousand aircraft, a vast, sweeping force, descended upon the western reaches of Icecrown Glacier like a dark, ominous cloud. This was the location of the Lich King's abattoir, a gruesome facility where countless corpses were processed through necromantic magic and crude stitching into abominations. Given the ample supply of Vrykul cadavers, the resulting abominations were particularly massive. Galen's objective was the complete destruction of this vital troop production line, aiming to cripple the Scourge's rapid expansion and alleviate pressure on the other three Alliance front armies.
The low altitude of Sholazar Basin had previously allowed the Scourge to conduct rapid aerial deployments via ropes from considerable heights. Now, the aircraft strained to gain altitude. Galen, mounted on Onyxia atop the Avalanche Mountain cliffs, waited patiently as the main body of his air force finally appeared overhead.
The undead Scourge swiftly detected the incoming invaders. Facing an aerial assault, a massive swarm of undead bats and gargoyles took flight!
"Da da da!" "Da da da!"
The aircraft operated in coordinated teams of twelve, utilizing their altitude advantage to engage the newly airborne gargoyles and bats. A gruesome rain of broken limbs fell onto the icy plains below. However, the sheer number of Scourge aerial units proved overwhelming. Despite significant losses, gargoyles managed to breach the aircraft's high-altitude machine gun fire, closing in and damaging the airframes. Aircraft began to suffer combat losses, with sporadic explosions erupting in the high altitude. Amidst the chaos, gnome biplane bombers seized opportunities to evade the gargoyles' sharp claws, releasing large, round bombs that rained down on the ground defenses. The intense air battle raged for an hour, until finally, no more Scourge air forces lifted off from the ground. The remaining aircraft, utilizing their superior maneuverability, evaded the grappling hooks launched by the giant abominations below, conducting repeated strafing runs and bombing sorties. The abattoir was reduced to smoldering ruins under the relentless aerial bombardment.
Galen observed the fighter group's performance with satisfaction. Instructing Onyxia to land, he directed the gnomes to begin leveling the remaining structures. A portal then shimmered into existence amidst the ruins, and a large contingent of dwarven and human artillerymen marched through, hauling their cannons. Galen planned to establish a permanent artillery position here. The abattoir's location within the mountains offered natural defensive advantages. By securing the mountain pass and establishing a comprehensive air defense system, this artillery position would become a strategic thorn in the Lich King's side.
Simultaneous with Galen's aerial assault, the Alliance army on Dragonblight surged forth from Wintergarde Keep in the east and Light's Hammer in the west, systematically clearing the crypt fiends that blocked their advance. Under the protective cover of the Sky City of Dalaran, they rapidly reached the outer defenses of the Wrathgate. Kel'Thuzad and Dar'Khan's Scourge floating cities were forced into a steady retreat, engaging the Alliance forces above the Wrathgate.
Deep within Icecrown Citadel, upon the Frozen Throne, Arthas sat encased in Saronite battle armor, Frostmourne resting across his lap. Arthas had initially used Frostmourne to shatter the icy prison, only to find an empty suit of armor within. Donning the armor and the Helm of Domination, he had then seated himself upon the Frozen Throne, merging with Ner'zhul.
A year had passed since that fateful merging. Arthas had experienced Ner'zhul's memories, his knowledge, his very being. Initially, Arthas felt his own soul on the verge of being crushed and consumed by Ner'zhul, whose soul had attained demigod status and possessed unparalleled mental fortitude. He realized the truth of Galen's words – the Lich King had orchestrated his path, step by step, to become the vessel for his own powerful soul. Arthas was the "perfect vessel."
To prevent his soul's annihilation, Arthas mustered all his inner strength and began a silent war for control of his own body. Initially, he was at a disadvantage against Ner'zhul's immense power. However, Arthas possessed a crucial advantage: the knowledge of Ner'zhul's weaknesses, gleaned from Galen. Furthermore, with his own capacity for good having been severed by Galen, he felt unburdened, powerful, and his mind and body were strangely purified, now aligned with a singular, potent evil. Arthas, devoid of inner conflict, fought against Ner'zhul, whose mind, despite its power, was ultimately flawed. The ideological struggle between them reached a stalemate.
While this internal battle raged within the Lich King, the Alliance had begun its ambitious campaign to secure Northrend. Consequently, in their perception, the Scourge was in constant retreat. First, Howling Fjord, where the Dragonscale Vrykul, initially poised to join the Scourge, were conquered by the Crusade. Then, the Borean Tundra fell to the Alliance, the strategic border of Ahn'Qiraj was captured, and the Scourge's mobile fortress, Naxxramas, crashed. The subsequent invasion of Sholazar Basin ended in failure, with the purification of the three Scourge commanders. This series of defeats forced Kel'Thuzad to consolidate his forces, inadvertently granting a reprieve to Zul'Drak, which had teetered on the brink of destruction. The frost trolls, who had been preparing a desperate final stand by invoking the power of their enshrined Loa, finally had a chance to regroup. Even the subterranean Nerubians, whose resistance had been spearheaded by a handful of stubborn Nerubian lords, now found a glimmer of hope.