Of course, Asad was aware that his Zombies didn't have enough strength to truly kill the Zombie Lord.
Nonetheless, with their indestructible status, Asad knew that he would be able to bind the Fleshrender for some time.
This would allow him to cast one of his strongest spells.
After all, despite heavily relying on his Grimoire, Asad was still a Necromancer who could cast various Dark Spells thanks to his Talent.
Now, seeing that his forces alone wouldn't be enough to bring down the Zombie Lord, Asad decided to borrow the hidden power of his grimoire.
This action allowed him to cast his spell three times its intensity or power.
Whoosh~
A page of the Grimoire vanished because of this action. However, Asad wasn't disappointed as he already expected this.