The "V" series of blood-powered machines were a prototype series of humanoid robots, designed for quick maneuverability and expert use of any weapon they can get. Only two of these machines were ever built, codenamed V1 and V2, respectively.
V1 is characterised by their blue color scheme, and are capable of instant self-repair and refuelling via the absorption of blood through their thin armor plating. In comparison, V2 is colored red, and has much thicker armor, but can't absorb blood.