The Leman Russ is the main battle tank of the Imperial Guard, and is also the most widely deployed tank in the Imperium. The tank is named after the Space Wolves Primarch, Leman Russ. The Leman Russ was first developed some time during the Great Crusade in the late 30th Millennium, but all information about the vehicle from that ancient time is missing or non-existent. The Leman Russ tank is the mainstay of most Imperial Guard armoured regiments and is produced by Imperial manufactorums across the multiverse. The tank is also used by other Allied members such as Irken Republic and the Vanu Sovereignty. Far from a sophisticated vehicle, the Leman Russ was designed and built with reliability and versatility in mind. It can survive the worst the galaxy can throw at it, and can run on almost any liquid fuel. Though slow, its frontal armour is strong enough to withstand the multitude of weaponry wielded by the enemies. Its side and rear armour remain thinner to reduce the strain on the tank's engines. This characteristic does make the Leman Russ vulnerable to assault from these angles, requiring infantry support, other tanks or very careful operation to protect the vehicle. The Leman Russ can perform to its optimum capabilities when all of these elements are during an Imperial armoured advance. The Leman Russ is crewed by a minimum of four crewmen, including a commander, gunner, loader and driver. Side sponson weapons may be added, each of which requires an additional crew member to operate. The Leman Russ is simple to operate, but very loud and uncomfortable for its crew. Due to the noise, intravehicle communication is only viable by an enclosed intercom system, with the commander having access to an external Vox-caster.
The Leman Russ was sometimes referred to world war 1 tanks and acted more of a support vehicle, though cheap and had several variants that fulfilled other roles, the diversity of the usage of the Leman Russ was one of its highlights. Though weakly armoured compared to something like the Tiger tank or M1 Abram, the Leman Russ should not be underestimated and was a great infantry support tank. In a combined arms force the Leman displayed excellent performance, although initial first multiverse war era Leman Russ battle tanks had communication problems. Over the course of the second multiverse war, the main battle tank received several retrofits including a quitter and more powerful engine invented by the Imperium's T'au allies who named the engine the XR-1. The XR-1 engine improved the Leman's speed enabling it to outrun even a Chaffee light tank enabling the Leman to be put into the a scouting role. Thanks to T'au inventions some Leman Russ battle tanks could use the Rail gun or Ion cannon improving combat performance along with the ability to detect stealth units. One unique Leman Russ the LR-A (As its T'au name is or the LAR by humans) was a Leman Russ mounted with a small side missile that had a small internal missile rack and allowed the LAR to engage both aerial and land targets effectively giving the Imperium a cheap anti-air gun that could engage threats from 7000 meters.