Skeletons on top of the walls used spears or stones to bring down most of them, but a few cruzados still managed to successfully scale the walls. They roared as they sliced through the nearest skeletons, but the undead still outnumbered them and managed to push them back, knocking them off the wall.
This was a mistake on the part of the skeletons. With no Crusaders on the walls, the mages who still had any mana left squeezed their last strength and bombed the top of the wall, destroying dozens of skeletons at once.
Dozens of deaths also meant dozens of cores self-destructing at the same time and releasing a fog of darkness over the walls that made it impossible for the Crusaders to scale the walls again.
It wouldn't last long, but it would be enough to obstruct anyone trying to climb in the next few minutes.