The ground below Layland cratered as his Mana pressure was too much for it to bear. The air explosion that the two Centaurs' Mana caused was no greater than his Mana did and it boggled the two to no end. It was baffling to them that Layland was not a Demon King's General despite his power. It was even rather comical for Ilschevar to not make him one.
Of course, there were some possible factors that they didn't consider. One of them was Layland simply not being strong enough to become one. The possibility was already appalling. They wished it wasn't the case because it would be a serious problem for them if it was. Ilschevar's army was already troublesome before. They didn't need it to become more troublesome.