Dealt

The leader was readying his weapon in preparation to attack along with his underlings. He wasn't planning on letting go of a clear advantage by ganging up on the boy. When it came to the mission, he would do anything without considering morals. There was no space for things like that in his work.

He took out a rapier from his dimensional ring and looked ahead at the two who had almost reached Leo. As he was about to lunge forward and close the gap between him and Leo, he noticed a ball of energy forming in Leo's hands. 

The ball was pretty small, but the energy it radiated seemed to instill fear in him even though he was a couple dozen meters away. The energy that was already powerful didn't seem to stop growing, making the ball bigger.

The two attacking Leo noticed this as well and were backing away from him, but they didn't have enough time.

"Fire Nova," Leo unleashed the spell prematurely before it could accumulate its full strength.