It turned out that when the scouts infiltrated the Watchtower on the first day, Drondheim's invasion of the undead had already been discovered.
The undead had been heavily injured by the armies of other countries on the previous battlefield.
A considerable portion of the warriors was unable to participate in the battle.
Therefore, when Drondheim's army attacked the city gates, the undead warriors did not show up. They were waiting for the lizardmen's rescue.
As for what conditions the undead offered the lizardmen to come to Nahrin Desert willingly to help the undead besiege Drondheim, the scouts who were captured weren't clear.
"Where are the injured undead warriors? Where are they?" Bunduk asked after listening to Angelo's statement.
"We're not sure either. They might be in the palace, or they might have been taken away by the lizardmen's ships," Angelo said helplessly.