The Pan-Pacific Armor Corporation was a multinational interest that was formed by a variety of weapons and heavy industry corporations that were concerned about the growing power of China within the Asian Co-Prosperity Sphere. The PPAC lobbied for contracts, supplying the ACPS with military gear, often to the detriment of Chinese firms. The PPAC was headquartered in Hong Kong, and had allies from as far west as the Indian Free State and as far east as Nippon (Japan) and Australia. Eventually the PPAC was dismantled through aggressive shadowrunning and cyberwarfare originating from China and from corporate competition and sabotage. Until the PPACs demise, the organization was well known and respected for it's cybernetics, mecha, power armor, and was a world leader in military robotics.
The Combat Robot
The development of combat robotics in the far east predate the Tycho Convention, and for the most part China and the rest of the ACPS was not very concerned with the potential threat for robots to rise up and destroy humanity. While the West continued working on power armor and super soldier programs, the combat robot was a primary military platform. The PPAC combat robot was noted for it's independent and autonomous nature, conservative combat strategy, and it's durable construction.
The Sanzang was the last main model combat robot produced by the PPAC. Standing just over 11 feet tall, it was a large machine, easily larger than conventional power armors, capable of mounting heavy weapons, and shrouded in heavy armor. The armor itself was stylized like a SE Asian Buddhist monk. The Sanzang was slow compared to other ground forces, but given the twin hard points for shoulder mounted weapons, and it's ability to carry heavy infantry support weapons as main guns, it had a massive amount of firepower available to it. This combined with it's high rate of accuracy and durability made the machine an initial success on the battlefield.
The principle load out of a Sanzang was an over the shoulder rotary missile launcher capable of firing a variety of missiles, typically favoring radar guided and laser guided short range high explosive projectiles. It had as a defensive armament am over/under heavy machine gun flamethrower longarm. This model, the SZ-1 saw large scale deployment and heavy use, especially across the islands of Malaysia, Indonesia, and was sold extensively to Australia, Nippon, and remains in production in India.
Armor-Buster - The Armor buster variant of the Sanzang carried an anti-armor guided missile launcher that fires a heavy anti-armor missile. The second mount is utilized to carry a normal medium range rotary missile launcher, and as a close combat weapon, the machine has a hydraulic fist designed to crack armor and shatter bunkers. This design is 30% slower than the main model.
Bushwacker - The Bushwacker is an Australian export model designed for speed and patrol duty and sacrifices both back hardpoints in favor of carrying a multibarrel rotary assault cannon, and a close combat hyperedge blade. The robot is popular for clearing out storm breaches, killing mutants, and facing other biological threats.
Starslayer - The Starslayer is a rare Sanzang armed entirely with energy weapons and a larger power core and stronger capacitors. The Starslayer mounts twin over the shoulder heavy infantry support lasers that have variable power output, allowing for concentrated fire or rapid area suppression fire. The close defense weapon is a supercooled plasma generator that functions like a shotgun style PPC. These are all secondary modifications to Nipponese Sanzangs.
The Sanzang is a fearless fighting machine, and isn't affected by things that cause fright, morale loss, or otherwise cause problems in military units. As a robot, it doesn't feel pain, it can't be reasoned with, and it absolutely will not stop. When directed by either remote operators or on the scene robot commanders, the machines can work to stunning efficiency networking out overlapping firing patterns, supporting artillery strikes, and generally acting as a machine army should.
In combined arms units, the Sanzangs excelled in the vanguard of fighting forces, acting as shields for infantry, power armor busters, tank hunters, and working defensively to prevent specialist fighting units from being deployed against friendly armor, mecha, or installations.
The greatest weakness of the Sanzang was it's complexity and ultimate price, the machines were expensive to build, costly to maintain, and were not easy to manufacture. The demand for the machine and a train of replacement and repair parts had the PPAC factories running full speed, and as such, made them vulnerable to shut down. This limited the effectiveness of the machine as fearing damage and long wait times on parts, the Sanzangs were not used as aggressively as they were designed to be.
Secondly, the PPAC had a single stunningly massive rival, China. Backing it's own megacorps, the Chinese government routinely ignored criminal activities carried out against the PPAC. As such, the alliance was besieged by mercenary shadowrunners, corporate hackers, and was a major player in a twenty year long bloody shadow war that raged between China and the satellite islands and powers it wanted to consume. This ranged from theft of technologies, assassination and kidnapping of key personnel, and sabotage of facilities ranging from viruses to actual paramilitary ops.
The Fall of the Sanzang
The Sanzang demonstrated it's final greatest weakness during the Taiwan rebellion. The Taiwanese rebelled against Chinese interests, and attempted to assert their autonomy from China with their token military forces. The core of this military power rested in several hundred Sanzangs. The conflict broke from tension to open hostility, Chinese hackers activated hidden codes buried in sabotaged Sanzangs, causing the machines to change sides to the Chinese, accepting Chinese military commands and firing on their Taiwanese counterparts.
This technological betrayal combined with the high cost of the machines spelled the end of the high end combat robot. Skeletrons would quickly replace the Combat Robot despite the fact that they are inferior machines. Being cheaper and less dangerous individually, they are less of a liability if hacked, and the majority of Skeletrons are cheaply enough made that hacking one cannot be done with remote gear, but requires an actual physical connection with the machine.
The main line combat robot was undone by it's complexity and cost, elevating the value of the human soldier either in power armor, a light mech, or as an augmented super soldier.
Future combat robots are less heavily armed, and much less heavily armored, as the threat of hacking or reprogramming remains a constant threat. Having one soldier going rogue is a problem, having a walking tank go rogue is something else entirely.
Fully functional combat robots still exist, but they are oddities, part of mercenary units, or function as chassis' for Seibertronians.
A 'Code 66' is the common term for a robot that has been hacked, and much much later turns on it's owners. This comes from the fact that the Sanzang was undone by an innocuous script in it's programming, code 66. The actual hacking that planted this code was done nearly two years before the Taiwanese uprising.