In the 1980s, Henschel Wehrtechnik initiated a private venture to develop an entire family of armored vehicles capable of performing a wide range of tasks on the battlefield. Three chassis were planned: the 4x4 TH200, the 6x6 TH400, and the 8x8 TH800. The TH200 was designed to carry either a 90mm gun or up to nine troops. The TH400 was designed to carry a 105- or 120-mm gun and otherwise could be used for troop transport, reconnaissance, or as an air defense system with the necessary modifications. The TH800 was designed to serve as self-propelled artillery with a 155mm cannon, as a heavy air defense system, or as a heavy armored personnel carrier.

Only one of the three variants was built: the TH400. In the 1990s, the hull received a turret armed with a 105mm gun, and it underwent various tests in 1996. After Rheinmetall bought Henschel, the wheeled tank was renamed the R400. The vehicle family never attracted any customers, and the R400 became a museum exhibit at the Dutch History Survives Foundation. Since the original turret was lost, the museum replaced it with a turret from a Leopard 1A5.

The R400 was introduced as a reward for the 2025 "Fast and Dangerous" event. In many ways, the R400 resembles other wheeled vehicles with poor survivability and weak armor. However, the R400 boasts a laser rangefinder, a thermal imaging sight, and decent mobility.