Poison?

Ryu shot forward, his speed leaving faint afterimages in his wake. Although he didn't use his great swordstaffs to fly, he couldn't be considered slow in the slightest. He simply preferred to maintain the flexibility of staying on his feet. 

Little Silk sat silently on his shoulder, her aura becoming more and more restrained. 

It didn't take long for Ryu to notice this at all. He could communicate with Little Silk, at least not in the usual way humans would. The only beasts that Ryu had ever known to speak were the Ancestral Beasts of Sacrum, but he had yet to meet such a creature in the True Martial World. 

Regardless, even without a clear line of communication, he could feel Little Silk's emotions and intentions. He had only traveled a few dozen kilometers into the core region, but her demeanor had completely changed, from one of excitement to one of restraint.