The upper class of these countries wanted to escape or surrender, but Du You would not give them the slightest chance.
After eliminating those Elemental Lords on the front line, Du You did not have the Elemental Lords lead the attack; instead, he let these Elemental Lords hide, using special methods to completely conceal their presence.
This way, the enemy had no way to discover their movements. With this world's level of power usage, they couldn't reach such high levels. Thus, Du You secretly transported the military forces to their Imperial Capital without them noticing.
"Very good, after waiting for three days, they have finally gathered."
