He startles slightly when the creature starts to crawl up his arm. Its unexpected even if he had sensed that it was with Xue Yang all along. He just hadn't believed it would climb up on him.

He settles his slightly elevated heart rate and tries to make sure his steps are smooth so the little creature doesn't get dislodged.

"He has no reason to distrust anyone." Which is a dangerous trait to have. Xingchen knows a little about that.