The Combine are frequently shown as cruel rulers over the citizens of Earth, suppressing dissent with brutality, policing using violence and using invasive surgery to transform humans into soldiers or slaves. Throughout the games, the player primarily battles transformed humans as well as synthetic and mechanical enemies that are the product of Combine technology. In addition to their role within the "Half-Life" series, the Combine have been adapted for machinima productions and one Combine character type has been made into plush toys by Valve.