Souls
The golems are made of the soil that was soaked with the black cursed blood of the undead creatures that were killed.
They are now carrying curses.
Avlyn noticed this and talked to her teammates.
"This kid is really vicious. The cursed soil. Even the godfather wouldn't use such a thing to deal with people."
"Well, that is why Godfather made a deal with this guy. But for that soil to be useful, it needs to go through the dome first.
Otherwise, it might as well be a normal golem." One of her subordinates replied.
"Of course that is true. Let's wait and see what happens."
As they talked the city also started its counterattack. They shot the spheres out of the cannons from walls at the undead creatures and the golems that numbered dozens.
*BOOM*
*BOOM*