Out of the darkness, the sound of combat carried to Karl's sensitive ears, as well as the Naga Warriors.
It was too faint for Thor to hear it, but Rae perked up, trying to find the source of the disturbance. It was out of sight, and Karl quickly realized that someone had found a low spot to camp in, where they wouldn't be spotted from a distance in the morning.
That was a much better idea than just camping next to a big rock, but if their battle was intense enough that it could be heard from kilometres away, they might need assistance.
But more urgently, the sound of battle was drawing the attention of all the creatures in the area. Once they started to move with purpose, it got the attention of even more, and soon every one of the creatures that Karl could detect was headed in the same direction.
Some would be passing right through their camp if they didn't move, and there were hundreds of them.