He could order his soldiers to scatter right now and the monster won't be able to catch up to them. It may be powerful but it is too big to move fast enough to deal considerable damage to the army.
He is just bitter that all that energy will go to waste. He had been considering using the 100 thousand to make his soldiers reach the mana entity stage. To leave the monster alone to die is to watch all that energy wasted.
"I'll hold it back while you join in with ranged attacks." He told his soldiers.
"To Victory." He shouted then he stomped off.
He heard the shout of reply from the army as he soared into the air. Jumping and landing have become very easy to do, now that he has eight gates to absorb momentum with. Still, his heart was hammering in his chest like an engine, but it was more excitement than strain. He felt the thrill of battle course through his blood vessels like the best elixir.