Zack didn't even have to aim, he just recognized the position of some enemies around and then used his inventory. In the next moment, countless fire swords fell from the sky from the back of the monster's formation to the frontlines. The monsters never noticed that until they were hit, and the swords exploded.
The explosions engulfed dozens of enemies at the same time and burned them to cinders. Zack had created them when he had equipped all of the fire related gear that improved that kind of element and stored them for a situation like that. Time didn't pass inside his inventory, so they kept their power for a long time.
Thanks to all that, the enemies were wiped out in no time. At leas half of them, the ones that resisted, began to burn or were unable to move, and the survivors in the area used that chance to counterattack and use every ounce of energy they had in store.
(You have reached level 260 and unlocked the skill Blast.)