While the M12 Warthog series of vehicles had remained the mainstay of the UNSC Marine Corps armoured units since its introduction, it had its limits. It was extremely bulky, a severe handicap in the urban terrain that the UNSC has found itself increasing fighting in, and though it excelled at offroad work and was an excellent all-terrain vehicle, its inability to easily navigate pre-existing roads made it a poor choice for urban combat. As such, the M13-X Lynx LRV was proposed by Sierra Space Systems as a supplement to the Marine Corps fleet of LRV's in 2531, and developed into two prototype models.