As the Yanibar Guard Army evolved and developed, a realization that its droid forces were sorely lacking took place in 23 ABY. To upgrade the obsolete Clone Wars models, two different droid vehicles were commissioned, the Predator and the Reaper. The Reaper was a dedicated anti-aircraft/anti-personnel platform, mounting a variant of the Starfire-PD naval point-defense weapon. Larger and more intimidating than the AATs it was replacing, its primary role was to defend against aerial attackers, protect convoys, and serve as a second-line support unit. The introduction of the Reaper marked a shift away from larger numbers of droid units into fewer higher-quality droid models.
The Reaper walked on 4 articulated legs in a manner similar to the older crab droids of the Clone Wars more akin to an arachnid. The high profile made it an easy target, but also provided the Starfire-PD turret with an impressive field of fire. A large sensor suite protruded from the vehicle's right side, while two navigational sensor modules were implanted near its head for guidance, terrain mapping and mine/obstacle detection. Heavy armor and deflector shields provided protection from hostile attacks. The same chassis that was used for the Reaper was also employed for the artillery/anti-vehicle Predator design.
Though marginally slower than the AAT, the Reaper was also capable of short sprints of fast movement up to 80 kilometers per hour, though not while firing in sustained mode. Its articulated leg design allowed it move across very rough terrain previously inaccessible to repulsorlift vehicles.
Although it was twice the size of the AATs it was meant to replace and somewhat slower, the Reaper was designed to combat larger threats, particularly aircraft. However, its repeating laser cannons proved equally adept at shredding infantry and other lightly-armored targets. The Reaper was capable of maintaining sustained rates of fire for up to thirty seconds before its turrets had to cool down, though that was ill-advised. As a secondary weapon, the Reaper carried a centerline sonic cannon on its Skyfire-PD turret and a series of anti-missile decoys and launchers that could be launched to divert or destroy incoming warheads.
The Reaper AA walker entered Yanibar Guard service in 25 ABY and immediately underwent field trials. Commanders were impressed with its ability to deal with aerial targets and lightly-armored ground targets alike as well as durability, but worried that it would be vulnerable to close-in attacks, particularly on its exposed head, which contained its central processing unit, or engines, or legs. While Kraechar Arms saw no way to add additional weapons and processing power to protect against close-quarters assaults. Instead, they simply mounted racks on each Reaper-AA walker to carry eight droidekas which could be deployed to handle close in-threats. Once neutralized, the droidekas could be stowed away via magnetic clamps until needed again later. This approach, while not a perfect solution, was considered adequate for the needs of the Yanibar Guard.
The Reaper AA walker first saw combat in 28 ABY on Rishi against the Yuuzhan Vong.