Kurogane Shiroikaze

NOWHERE in the episode they mentioned Sheryl was a cyborg. What was revealed was that Sheryl has the V-type infection, and she was taken in by Grace as a test sample, possibly for trying out the new medicine. The "witchcraft" table that Michel took was actually an experimental drug to cure, or at least treat the infection, so it's implied that without Grace's supply, Sheryl will soon succumb to the disease. As for what the "V-type" infection means, it wasn't revealed yet.