The Network of bones probably worked as a conductor to make the undead king control his minions completely… there was also a chance that he was down there. Heading there to kill him and end the battle as fast as possible was probably the best option, but it wouldn't be easy with so many enemies around.
"The giant skeletons can only move within a certain area," Rain said while using Telepathy to talk with the others. "Use this to your advantage."
Soon after, Rain told his squad members to focus on the legs of the monster. So far, only one of them was targeting his group, so they needed to hurry up. When the beast saw Rain approaching once more, it soon readied itself for the battle. But then, all of a sudden, Rain disappeared after touching the ground one more time.
