There are two reasons for their downfall: first, the key phrases became useless, and second, they were too fragile. A wide-scale spell coverage meant they were almost dead on contact.
Duge sensed this massacre but showed no reaction. He could teleport into the battlefield, but without a clear understanding of the situation on the Heavenly Court's side, he didn't want to take the risk alone.
Compassion does not take command in war. There is victory and defeat in battle, and it is impossible not to have casualties.
Just as Emperor Yuan Sheng launched a surprise attack on the allied forces of the three clans of the Middle Heavenly State, the Demon Emperor successfully activated the Primordial Banner and moved over three hundred thousand Heavenly Soldiers and Generals beneath the illusory shadow of the Jianmu, directly sending them into the encirclement at Mount Sumeru...
