Siege of the Imperial City ( 4E 49 ) The Siege of the Imperial City was a battle that took place in 4E 49 , forty - nine years after the Oblivion Crisis . The battle was fought between the Imperial Legion under Emperor Titus Mede I and Lord Vuhon ' s ( aka Lord Umbriel ) undead army , which was composed of re - animated Argonian s , Dunmer , and Imperial legionnaires . Prelude . Arrival in Mundus . After bringing the floating city of Umbriel into Mundus from Clavicus Vile ' s realm in Oblivion , Vuhon destroyed the city of Lilmoth in Black Marsh to gather souls to power his Ingenium in order to keep Umbriel afloat , and to gather bodies for his undead army . He then directed the city northward through Black Marsh , destroying the cities of Stormhold and Gideon along the way before crossing into Morrowind , Vuhon ' s homeland . He hoped to find the Umbra sword in the ruins of Vivec City , as it was the only thing that could destroy Umbriel and himself . After capturing Sul and Prince Attrebus Mede and finding that the sword was no longer in Vivec , he turned the city southwest towards the Imperial City , sending his undead horde to besiege it before Umbriel ' s arrival . Vuhon needed to bring the city to the White - Gold Tower in order to break Clavicus Vile ' s hold on the city , as it was technically still in a " bubble " of Oblivion , and the Tower , as one of the axes of the creation of Mundus , could emancipate Umbriel from Oblivion . He sent an undead minion to the Emperor with an ultimatum : he would permit everyone to leave the Imperial City unharmed , so long as they gave him the city . Emperor Mede refused and prepared the Imperial Legions for battle . In fact , Mede had been aware of Umbriel before it even attacked Lilmoth . Despite his son Attrebus ' demands for action , Mede had refused since Black Marsh and Morrowind were no longer part of the Empire . However , he sent mages escorted by legionnaires to survey the city just in case it turned towards Cyrodiil . When it did , the scouts fell back as Umbriel destroyed Cheydinhal . The siege . Skirmish northeast of the city . Commanding the Legion ' s skirmish was General Takar , a Redguard from Hammerfell . He led his forces , five thousand soldiers made up almost entirely of cavalry and mages , northeast of the Imperial City to meet Umbriel before it reached the city . With Takar were eight wagons containing unknown engines . As the cavalry charged the undead lines , the mages took to the air with the wagons , flying straight at Umbriel . Within its bubble , Vuhon ' s flying " Taskers " appeared in huge swarms and slaughtered the mages before they could get close . After that General Takar sounded the retreat , and Umbriel proceeded undettered towards White - Gold Tower . The Synod and College of Whispers made two more attempts to attack Umbriel by air , without success . Battle on the shores of Lake Rumare . Two days later , Umbriel arrived at the Imperial City . Several Legion detachments under Commander Prossos were deployed along the shores of Lake Rumare to attempt to hold the undead . While the disciplined legionnairies were able to kill several times their own number , the enemy kept on coming in endless waves . A battalion of spearmen was able to repel an attack on the main gates , but the undead turned their assault to the northeastern wall near the Imperial Prison where Umbriel was floating over the walls . There , the Twelfth Legion was pushed back to the walls of the city as countless thousands of undead surged against their shield wall . Fall of Lord Umbriel . Inside Umbriel itself , Sul , Attrebus and Mere - Glim discovered that Vuhon had stored his soul within the Ingenium itself along with the Umbra entity , and only by stabbing it with the Umbra sword would he be killed . Mere - Glim attempted to use the sentient Hist - like trees in the Fringe Gyre to move Umbriel out of Mundus , but Vuhon sensed his attempt and used his magic to prevent it . The trio managed to reach the Ingenium in the heart of the city , and while Mere - Glim and Sul held off Vuhon , Attrebus drove the Umbra sword into the Ingenium . Vuhon ' s soul and the Umbra entity were drawn into the blade . Attrebus was then possessed by Clavicus Vile , who planned on claiming his soul and taking Umbriel back into his realm of Oblivion . However , Sul attacked Vile , who stabbed him with the sword , causing Attrebus to let go and Sul to fall onto the Ingenium . Vile released Attrebus and claimed Sul ' s soul instead . With Vuhon dead , Mere - Glim was able to use the Hist - like trees to take Umbriel out of Mundus into the realm the trees originated , not Vile ' s realm . As soon as Umbriel left Mundus , the undead army besiegeing the Imperial City simply fell where they stood . Outcome . The Imperial Legion was victorious , which resulted in the end of the Umbriel Crisis . While Attrebus and his companions were responsible for the end of the Crisis and the battle , he decided to give credit to the Synod and the College of Whispers , as the two organizations had worked together for the first time during the Crisis , and he wished for them to be on good terms for the good of the Empire .