During the initialization of the offense at Nethergarde, the Crimson Storm executors demanded that the alliance stop sheltering traitors and those who defected from Dalaran's side to aid in the attack on Warsong Hold. The Crimson Storm demanded that the traitors be handed over to their custody, and Nethergarde would be spared. One Dawn Lord Heinz Guderian, however, refused to sacrifice human, gnomish and indeed Draenai lives in order to stop what was perceived as a Horde agression on Stormwind lands.
The Dawn Lord called out to the people of the alliance and held a great council of war. For details of what happened within this council, you will have to ask the Lion Shield members themselves (as they organized it themselves, and I shall in no way take credit on their behalf).
It was, however, deemed that Nethergarde was far to important a strategic location to simply give it up to the Horde. The Lion Shield was born to defend Nethergarde from the Crimson Storm, and whilst it did indeed recruit soldiers and mages from Ashenvale, Dun Morough and Arathi - Most of the members of the Lion Shield were Stormwind Humans, Lordaeron Survivors, Humans, elves and gnomes from Dalaran and mages from the Exxodar who had come to sympathize with all who suffered attacks from what they perceived to be malicious Sin'dorei. The leaders for theese Draenai - aswell as being personal ambassadors from their people to the Violet city itself, were none other then Mistress of Arms Kimbalin Raschan and Grand Arcanist Perlin of the Ebon Flame.
The Lion Shield stood victorious at the battle of Nethergarde, forcing most of the Crimson Storm forces to retreat north. The Lion Shield forces were a defensive act, and despite the protests of many men and women - neither Dawn Lord Guderian - nor the Mistress of Arms Raschan, allowed the Lion Shield forces to pursuit the Crimson Storm nor to attack the Horde outpost of Stonard.
Upon the fields of the Blasted Lands the supreme commanders of the Lion Shield and the Crimson Storm - Mistress of Arms Kimbalin Raschan and Warlord Antus Draconus challenged eachother to a duel of epic feats to settle a personal vendetta. Both sides demanded that non interfere.
Meanwhile, Arcanist Perlin and Magistrix Verdande unleashed terrible and powerful spells onto eachother, a testament to the destruction and power that surges from the Sin'dorei Blood Mages against the controlled and millenia-perfectioned wisdom unleashed by the Draenai Arcanists.
At the end of the day, Arcanist Perlin bested the Magistrix Verdande with arcane superiority, making the phoenix flames backfire and sending the Magistrix into retreat. At the same time, the Warlord Draconus brought the Mistress of Arms Raschan to her knee's. As per their personal agreement, the Warlord Draconus was allowed safe passage for the retreating forces back into the Swamp of Sorrows, with a promise between the two commanders that they would one day meet upon the field of battle once more.
The Blood Knight and the Forsaken offensive commanders, Serian Blackwater and Elturion Sunfighter led the exodus from the Blasted Lands back to Lordaeron, with the Iron Ring quickly extracting their most prominent members from the site of battle. The Lion Shield has thus intended to make their presence known in Northrend.
Credits go to Poesi.