Magnus: Dragon Prince
With it being dark they weren't able to see 3 creatures stalking them.
When Rex saw what made the sound, he was terrified. The creature wore a torn shirt and pants with a tatty hood over its head, the 3 creatures seemed to be making clicking noises at each other, like they were talking to each other, they had long skinny arms, and 3 claws on each hand. Their faces were mostly hidden, but Rex thought he saw one of them with a beak. As they came closer up the hill 2 of them walked in opposite directions to box them in.
"S**t!" Markus said, "Crazaks! Odd they are so far away from their den. They are creatures from the desert."