While Leon was busy blaming himself for Gisela's misfortune, William threw her away and jumped to attack Leon. At the same time, Leon felt his body moving toward him. That caught him by surprise, but using earth magic, he counter-attacked whatever was making his body move.
Leon put the fireball in front of himself, and the flames engulfed William. However, much to Leon's surprise, William crossed the flames almost unscathed and tried to grab Leon's neck... only to get hit by a massive block of earth that sent him flying to the streets of New York.
"... How can he endure the flames that can melt steel?"