Yuriel
Originally, Zick had no intention of killing many people for no reason, he was not a genocidal person. He did all his actions after thinking of the profit coldly.
Seeing that the body he had was not enough, he could only come down to carry out a slaughter to Levienel.
Zick knew the general limit of the biological golem so he ordered a number of corpses according to it.
The biological golem was made with a certain limit in mind so that no mishaps were occurring. This was set by the alchemists of the old alchemy tower.
If there was no such limit, Zick would have of course gone on a massacre with no second thought. There was no need for further consideration. To Zick, his well-being and benefits were the most important, above everything else.
Even the ten thousand corpses that Zick used didn't have a high chance of strengthening the golem. Zick was just being optimistic a while ago.