The Zentraedi were created for the sole purpose of war. Although they had their origins in manual labour, their creators, the Robotech Masters, had always intended to use them to allow the Robotech Elders to seize power. In 1361 CE, the Robotech Elders used their army of loyal Zentraedi clones to overthrow the Tirolian senate. As they were clones, the Zentraedi could be bred at an incredible rate and they developed quickly, reaching adulthood after only a few months. Measuring on average 45' (13.7 m) tall and able to withstand extreme environments, the Zentraedi were viewed as the perfect warriors and very quickly they were able to destroy all pockets of resistance to the Robotech Elders. Once in power, the Robotech Elders continued to increase the size of the Zentraedi army and developed new mecha and ships for them to use, but they totally segregated the Zentraedi from Tirolian culture. Not wanting anything to interfere with their "perfect" warriors, the Robotech Elders prevents the Zentraedi from interacting with normal Tirolians and even prevented the two Zentraedi genders from serving together, creating two Zentraedi forces, one male and the other female, although both were under the command of the Zentraedi leader Dolza.
Knowing nothing but war and aggression, most Zentraedi did not realize that there was another way of life. They were trained since birth to avoid the Tirolians when they were not being given orders and they were trained not to pay close attention to the planet's that they conquered outside of military objectives. Zentraedi never received shore leave and few knew the location of Tirol. This left the Zentraedi extremely vulnerable to culture shock, which is exactly what happened during the Ci'Vonian crisis. In 1519 CE, two large Zentraedi forces, totalling 200,000 ships were so impressed by the Ci'Vonian culture that they broke away from the Robotech Elders and joined forces with the Tirolians on Ci'Va. Their defection led to the centuries long war that led to the replacement of the Robotech Elders with the Robotech Masters and the creation of the multi-million ship Zentraedi armada.
To deal with the Disciples of Zor, as the Ci'Vonians and their Zentraedi allies came to be known, the Robotech Elders ordered the Zentraedi armada enlarged. Numbering less then 800,000 ships when the Zentraedi fleet joined the Ci'Vonians, the Zentraedi armada slowly and steadily grew over the centuries of warfare until it had reached just over six million ships by the time the Disciples of Zor were finally defeated in 1940 CE. Once the Ci'Vonian crisis began, the Robotech Elders, and later the Robotech Masters, became obsessed with keeping the Zentraedi free of any cultural contamination. The Zentraedi were given explicit orders not to interfere with other races and cultures unless explicitly ordered to do so by their Tirolian leaders. For the most part this policy worked and no further cultural contamination occurred until the Zentraedi arrived in the Sol System looking for the SDF-1 Macross, the last source of viable, fertile seeds for the Flower of Life.
Although cautioned against any contact with the Humans, or micronians as the Zentraedi called any race that was the same size as the Tirolians, Breetai, the leader of the Zentraedi division in search of the SDF-1 Macross, was forced to in order to accomplish his mission of capturing the ship. However, over the course of several years of conflict and contact, the Zentraedi in the Sol System, which by 2011 CE included the million ship Adoclass Main Fleet, became exposed to Human culture. In 2011 CE, the situation came to a head when Breetai ordered a ceasefire and entered into peace talks with the RDF on the SDF-1 Macross. In hopes of avoiding a second incident like the Ci'Vonian crisis, Dolza, still the supreme leader of the Zentraedi, marshaled the Dolza Main Fleet and as much of the Gorg Main Fleet as he could and folded to the Sol System to confront Breetai. By the end of the battle, Dolza was killed and the proud Zentraedi armada was reduced to only a handful of ships trapped in the Sol System. Within a few short days, the one thing that had allowed the Robotech Masters to cling to power had been destroyed and their warrior race could no longer protect them.
For most of its history, the Zentraedi enjoyed being the largest and most powerful force that anyone had encountered. The size of the armada allowed the Zentraedi, and their Tirolian masters, to through away Zentraedi life when necessary and all Zentraedi tactics reflected this. Massed assault and overwhelming numbers was often how the Zentraedi won land battles, but space battles is a very different story. Forced to fight other Zentraedi during the long war against the Disciples of Zor allowed the Zentraedi to develop advanced space tactics and strategies. Their enemy was elusive and conducted hit and run raids almost at will, enabling them to concentrate their forces wherever they chose and forcing the loyal Zentraedi continually on the defensive, but it also taught the Zentraedi valuable lessons. The Zentraedi became experts on space warfare, but again, the limited range of thought that the Tirolians allowed the Zentraedi forced them to narrow their tactics on locating an enemy and destroying it quickly. When the Zentraedi were used to attempt to capture the SDF-1 Macross starting in 2009 CE, they were at a complete loss. Even one of the Zentraedi's most able commanders, Breetai, and a fleet of several thousands ships, which was eventually increased to over a million ships, could not capture the ship. Capturing a ship intact was far removed from the standard mission and Breetai struggled for over two years to accomplish his mission before the cultural contamination of his fleet forced him to side with the Humans against Dolza and the uncontaminated Zentraedi.