The XR-85 Tank Droid was originally designed to deal with civil unrest on Imperial worlds. When designing this war machine most programmers assumed that the tank's programming should be based on the "Event Pathstreaming" model, which is used for assassin droids. Tank Droids that were based on that model never achieved the the kind of long term independence and reliability to make this a cost effective investment, since ground combat is very chaotic and the number of choices is swamped by the cognitive units. The early prototypes were extremely expensive to mass produce. These prototypes were far smaller in size to the Tank Droids that would be used by the Empire after the Battle of Endor.

    The Tank Droids employed by the Empire before Endor and were small enough to allow multiple Tank Droids to be transported by a Sentinel-class Landing Shuttle. The Empire used these droids to defend some of its bases and these droids were also used to attack the Rebels. Although it is vulnerable to an air attack, it can defend it self against them. These droids were developed and in use over six months after the Battle of Yavin. Unlike its predecessor, these Tank Droids were are far more weaker in destructive power. The XR-85 is quite useful in urban assault operations, were its independent treads will allow it to turn in tight areas and its armour plating lets this droid plow through anything. This droid is virtually unstoppable. The design of an effective sentient tank has been on the minds of Army planners for decades. Tireless, undistractable, implacable and adaptable to any situation without constant referral for update orders, the Tank Droid has been one of the longest running projects for Imperial Scientists.

*After Endor* As the technology was refined, these droids eventually became inexpensive and practical to mass produce for combat. This breakthrough happened during Grand Admiral Thrawn's return, however his campaign drew attention away from this new technology. It was only when Chief Engineer Umak Leth was called before the Emperor that it was pushed forward and pressed into combat. This droid's brain is a pirated Industrial Automation R7 Droid Brain Pathway Matrix design which gives the XR-85 the needed independence factor and it also made this droid one of the few droids with sophisticated intuition programming. The drive system gives the tank incredible traction and its internal seals allow it to travel in water up to 15 metres deep. The Heavy Particle Cannon can level troop bunkers with a single shot, it is backed up with two Light Turbolasers which are typically used on repulsor tanks or walkers. The four Twin Heavy Repeating Blasters are for dealing with speeders and enemy infantry. The final weapon is the DF.9 it is for anti-personnel purposes. Each of the weapons are powered by a separate power generator giving the droid virtually unlimited firepower.

    The Empire's first priority was the war against the New Republic, Imperial Governors received the untested XR-85 units and discovered that they were brutally effective, motivating Imperial Command to promptly send them to the front lines. As successful the CAVs were in maintaining control throughout the Galaxy during the long Civil War and the Mutiny, in many situations there have not been enough trained soldiers to make efficient use of them. As a cost cutting measure the Empire decided to increase the number of battle droids to fill out the ranks in the Imperial Ground Forces. While combat performance consistently shows that there is no substitute for an organic pilot, these tank droids are superior at combat than earlier generations of similar combat machines.