Battle for the Undercity

Prelude
Shortly after the battle for Angrathar the Wrathgate begins and is slain by the Lich King,  appears on a cliff overlooking the battlefield and uses Forsaken catapults to unleash the newly developed plague on the unsuspecting forces gathered below. The losses on all sides are great, and perhaps the greatest loss is the death of the Alliance hero.

Soon after, it is revealed that and several members of the Royal Apothecary Society had sided with Varimathras, who had secretly remained loyal to his nathrezim brothers and the Burning Legion while serving under. Together, the two had orchestrated a coup d'état and forcefully taken control of the Undercity, nearly killing Sylvanas in the process.

Horde
Determined not to allow the dreadlords a foothold in Horde territory, Thrall and Sylvanas planned an immediate counter-attack. In the midst of their planning, arrived bearing terrible news: in the wake of 's death, King Varian was preparing for a possible war with the Horde. assured Jaina that the Horde had no official interest in war unless provoked and that he would ensure that justice would be done.

After informing the Alliance diplomats that the Horde was not responsible for Grand Apothecary Putress' treachery and that only the Lich King would gain if the Horde and Alliance were to fight one another, Thrall along with Sylvanas and led the assault into Undercity itself to reclaim it for the Horde. After fighting the Forsaken rebels and the demons within, the combined might of the Horde slew the traitorous demon.

Alliance
After receiving word of 's death, Varian was overwhelmed with anger and sorrow, having considered Bolvar a brother ruling his kingdom and raising his son for years. He sent Jaina Proudmoore to Orgrimmar to discover the reason for the Horde's betrayal, which he deemed an act of treason and demanded retribution for his friend's death. Jaina returned and informed Varian that Varimathras and the Royal Apothecary Society had betrayed them all and the Horde no longer controlled Undercity. Having already ordered an assault on Undercity while Jaina was away, King Varian deemed that not only was it the perfect time to bring Bolvar's murderer, Grand Apothecary Putress, to justice, but to also retake Lordaeron for the Alliance as well.

Varian and Jaina gathered the Alliance army and attacked Undercity, hoping to reclaim it as Lordaeron for the Alliance and bring Putress to justice. When entering Undercity, Varian becomes disgusted by the condition of the once great city, which he knew since childhood. Tracking Putress to the Apothecarium, Varian and Jaina defeated him. But, to Varian's horror, they also discovered dozens of mutilated and defiled human corpses, on which the Apothecary Society experimented to create the New Plague; realizing that although the Alliance and Horde agreed to a small truce over the years, the Forsaken had been secretly creating a means to kill them all.

Aftermath
Ultimately, both and  were killed, and Varian confronted Thrall and Sylvanas in the Royal Quarter. Battle ensued, though Lady Jaina Proudmoore intervened by freezing the combatants solid and teleporting all Alliance forces out.

The Battle for the Undercity ended the cold-war between the Alliance and the Horde, with King Varian's declaration of war.

Meanwhile, in order to ensure that no more Legion-aligned abominations crawled out of the Apothecarium, Thrall sent a legion of Kor'kron Guard led by to occupy the Undercity, guarding it from threats outside, and from any that may remain within following The Battle for the Undercity.

Years later, the Alliance would attack Lordaeron and the Undercity once again in the Battle for Lordaeron.

Units
🇨🇴


 * Burning Legion
 * Legion Dreadwhisperer
 * Legion Overlord
 * Legion Invader
 * Treacherous Guardian
 * Perfidious Dreadlord
 * Failed Experiment
 * Apothecary Chemist
 * Apothecary Collaborator
 * Plagued Felbeast
 * Blight Spreader
 * Blight Slinger
 * Ravishing Betrayer

🇨🇴
 * Horde
 * Warsong Battleguard
 * Horde Demolisher
 * Horde Demolitionist


 * Alliance
 * Stormwind Elite
 * Alliance Siege Vehicle
 * Alliance Flying Machine

Forces

 * Alliance
 * 1 Warrior
 * 1 Archmage
 * Adventurers
 * Footmen, riflemen and gyrocopter(s)
 * 1 Night elf druid
 * 1 Blood elven rogue


 * Horde
 * 1 orcish shaman, Far seer and Warchief
 * 1 Dark ranger
 * Orcish grunts
 * Horde Demolishers
 * Adventurers
 * 1 Shadow Hunter


 * Burning Legion
 * 1 Dreadlord
 * 1 Dark Apothecary
 * 1 Flesh giant
 * 1 Doomlord
 * 1 Engorged Blight Worm
 * Hundreds of lesser demons and undead