Ordinary zombies are much weaker than their original forms, just like that Balor Flame Demon zombie, which was quickly chopped into pieces by its peers.
So while there's a huge mass of zombies, their actual combat strength is just so-so; a fireball thrown into their midst can easily blow up a large number.
But the sight of these fearless undead hurling themselves into the fray is still quite shocking.
The demons were caught off guard and were heavily suppressed for a while.
Amberser wasn't going to let this opportunity slip by.
All sorts of powerful magic spells rained down from the sky, causing the group of demons to howl in chaos.
Large areas of deadly poison fog appeared above the heads of Minor Coward Demons, causing them to emit plumes of white smoke, their skin to ulcerate, and then their flesh to turn to pus, leaving only white, bony skeletons.
The skeletons then rose from the pus and continued to serve Amberser.