"Kael'thas, you must make up your mind now," said the Midnight Mage. "Either you return to Dalaran and keep out of this matter. After all, the Sun King is still the King. If Silvermoon City falls, it's on him. You can just wait to succeed and clean up the mess in Dalaran.
Or, you have to take drastic measures and find a way to command an army. Only then will you have a chance to save Quel'Thalas. Otherwise, no matter how powerful your magic is, it's useless on your own. No matter how good your ideas are, they're useless without the support of an army."
Kael'thas nodded in agreement upon hearing his apprentice's words. The Midnight Mage was right; he needed an army of his own.
Typically, commanding an army would be an easy task for him as the Crown Prince of Quel'Thalas.
Unfortunately, the Sun King disagreed, focusing solely on the defense of Silvermoon City without considering fighting outside its walls, making it difficult for Kael'thas to attain command of the troops.