After announcing this to the world, the Shadow Tower quickly began to prepare for war.
Out of the six Wizards stationed in the tower, two were selected. They recruited close to 100 formal and unofficial Apprentices, and the Sixteen Kingdoms under their banner, the edge of the forest, had five human kingdoms. The scale was so large that they had invested close to 10,000 soldiers in total.
As their enemy, Red Devil's Blood only had one formal Wizard and dozens of Apprentices. The human kingdoms under their rule only had two human kingdoms, Jed and Ryker. In total, they had less than 5,000 soldiers that could fight.
But don't think that this was too weak. Red Devil's Blood was already one of the top five powerful Wizard organizations in the Underdark Treesea. It was much weaker than this.