Three hours after Thirteen closed his eyes, he felt his body being shaken by someone.
Since he had already prepared for this possibility, he didn't sleep too deeply in order to ensure that he would be ready to react at a moment's notice.
He glanced at Cristopher. Instead of saying anything, the chubby boy pointed at the sky.
Thirteen followed the direction he was pointing at and saw three Flying Monsters in the sky.
They were circling around the Oasis, and although they were too far for him to discern what type of monster they were, he could estimate that they should at least have a wingspan of five to six meters.
'They have long necks, so they might be Condors or Vultures,' Thirteen thought.
Condors and Vultures were basically the same species. However, the term Condors was used for very large Vultures, and from what Thirteen could tell, these Flying Monsters would be at least two meters tall if they stood on the ground.