The Siege of Dalaran was staged by the Blue Dragonflight to weaken the Kirin'Tor in their capital city. The event will be remembered as one of the bloodiest and most destructive throughout the history of Northrend's invasion, nearly decimating the whole city.
Due to reasons not able to be explained to all, Yakob Merres and Salen went to Dalaran to tell Rhonin that the Blue Dragonflight was going to attack Dalaran. At first Rhonin was skeptical and inquired as to how they knew this, but Yakob and Salen could not tell them about how they got hold of such information until a later date. The Argent Crusade and Ebon Blade, plus Horde and Alliance, sent their elite to gather in Dalaran in preparation for the Blue Flight. Division Six as it was called, played a major role in the defense of the city and part of it's safety depended on Yakob the Brave, Salen the Merciless, Aylana the Kind - and some magi associated with the Kirin'Tor, namely Ambassador Nemain and Magus Keldaron.
The attack was to be based purely on coincidence and the groups gathered, forging weapons and crafting their armor of the highest quality. The magi of Dalaran readied a large arcane shielding nicknamed 'Big Bubbly Bertha' to cover the city from airborne draconic enemies.
The attack happened soon after the preparation. All forces of Division Six were sent below Dalaran to investigate draconic sightings, but little did they know it was a trap. As they discussed below, dragons appeared from over the mountains. Enormous rifts of pure magic sliced through reality and formed next to Dalaran, hundreds of dragons and their mortal servants pouring through to meet the defenders of Dalaran. Krasus Landing was first to be hit, the Mage-Lord slicing a hole into space and making a rift form. Legions upon legions of Blue Dragonflight minions poured through to prepare for a counterattack. The second was the bank on the Silver Covenant's side. The Portal Keeper used a special crystal to implant his magic within it and connect with the portal, dragons swiftly following through. The last, but not least, was within the Violet Citadel itself.
Cyanigosa, the supreme commander of the forces invading lay within. She called upon her magically attuned children to rain death on Dalaran. The invasion began and the defenders were MASSACRED. The dragons split the Kirin'Tor, trapping them within their own city. They crumbled the archways of the Silver Enclave and Sunreaver's Sanctuary, shredding through the mortal ranks of the mages. The mages stood no chance against the dragons, sent flying into buildings - the majority being killed by magical attacks. Some were lucky and survived, but the trauma to see all their kin killed drove them insane. The streets of Dalaran were littered with dead bodies, the buildings crumbling as fires spread the area. The pathways had bricks missing, some of the pathways completely obliterated. The Blue Flight had no mercy at all, never yielding in their total destruction of the once proud city. The once majestic spires of Dalaran were sent shattering to the ground, mage and dragon alike being crushed under the mercy of gravity.
Dragons from below the city struck at the bottom of Dalaran, sending quakes rippling through the city. Spires and buildings cracked under the constant magical earthquakes, toppling on eachother. Sooner or later, the whole city turned into one of the most bloodiest battlefields EVER to grace Azeroth, dragons and mortals littering the brick roads of Dalaran. The sidewalks were stained blood red, most of the air contaminated by magical energy. During the battle, rocks flew overhead as dragons were sent crashing into buildings. The Sunreaver's Sanctuary was nearly destroyed completely, one of the spires cracking along the spine.
Division Six saw the dragons and ran for the portal back to Dalaran. They swiftly ran inside and saw the total destruction that was left in the wake of the Blue Flight. Completely shocked, they split up into sizeable groups and ran for the Mage-Lord along with the Portal Keeper. Afterwards, they charged the Violet Citadel to take Cyanigosa. A heated battle resulted, leading them to the Sewers. Once inside they discovered Krasus, the very Consort of the Dragon Queen Alexstrasza. The more.. intelligent ones.. were shocked at this discovery and they eventually attacked him. He was quite powerful, spewing flame and wind. In the end, he was overwhelmed and killed.. the Siege of Dalaran ended.
This bloody battle took the lives of many, including several high ranking members of factions, in particular, the loss of Argent Confessor Paletress. After the battle, many flocked to the site of her body, Yakob and Aylana included. Yakob took her body to Lights Hope Chapel through means of portals to have her buried. To this day, she still lies there, her grave now becoming a regular pilgrimage site for many wandering Light-followers.
More than just lives were lost in the battle, several notable structures in Dalaran were also destroyed. Large portions inside the Violet Citadel were destroyed due to Cyanigosa, many of the large spires were toppled over and portions of the Silver Covenant compound and the Sunreaver Sanctuary were greatly damaged. However, the greatest blow to the morality of the Kirin Tor came from the destruction of the statue of Archmage Antonidus. Slowly but surely, the Kirin Tor are working to rebuild it to its former glory.