Ryuu was a result of an experimental accident that involved a bat and some other organic materials. Ryuu gain strength, size and intelligence. (Ryuu does understand speaking language but can't talk)
He developed a stinger with a poison that causes paralysis for a short period of time.
He also has the ability to produce dangerously high pitch creaming sounds painful to humans and also high speed frequency sounds painful to werewolves and other high frequency sensitive creatures.
There was a time were Ryuu was captured and used as a living anti-werewolf weapon. However, he manage to escape.

his markings glow, he has green tongue, has a cautious nature. He prefers to strike his victims with his stinger paralyzing them and calmly feast on their blood while they're still alive

I'm gonna add some cellshading later on ^^