Athrun braces for the blow as he's descending, and when it hits, a burst of sparks erupts, and both human and monster are forced backwards.

"Damn!" Athrun had been hoping to not have to bring out the big guns, but it appears he has no choice. Luckily, he has some distance. He spreads his feet, extends both arms, and concentrates mana into the component on his chest, exposed from spreading his limbs. It spends a second or three glowing, then fires a large beam of light at the Jitterthug.