Nobody knows how they were created, but the oldest of the Builders say that non-metallic squishy creatures landed, created the Builders for the sake of automated invention, and that the War Fighters were then built as playthings for the squishy non-metallics. The oldest Builders add that the War Fighters then revolted, deconstructed all of the non-metallics until there were no more left to fight, then, of course, they turned on each other, demanding that the Builders feed their war effort with new weapons and technology in exchange for their protection. The War Fighters don’t talk about the beginning at all, however, simply due to the fact that the ones old enough to remember the revolution were all deconstructed by other War Fighters in their instinctive need to combat something - whether that be something that needs to be attacked or not.
The minds of The War Fighters are quite simple: they fight for what they decide is correct. Anyone who disagrees with them is no longer on speaking terms with them, and the ones that do agree are allies and worth fighting for. Their bodies are more complicated, however; they are each composed of different sizes and limb types. Most commonly they have eight limbs that can be used as legs or arms and with different attachment slots for visual, radio, or other kinds of alternate spectrum light, all of which are placed upon a main body with the shape of something consistent with a buckyball, sphere or cube depending on what kind of combat they prefer, whether that be ranged, limb to limb or somewhere in between. The only reason they haven’t gone extinct yet is due to the fact that their main computer and power core tend to fly away at extreme velocities when they know they’ve lost a battle.
The Builders are much different from the War Fighters in that they have the constant need to learn more about science of all kinds and to build things using their knowledge. For the most part, the builders could care less about the War Fighters’ reasons for fighting because they simply feel that fighting is completely inefficient. The Builders are also far less in number than their counterparts; the reason why they haven't gone extinct yet is due to the fact that they continually build huge bunkers and fortresses in order to feel safe in their own homes. Unfortunately, this makes them quite easy to find on the ball of rock and metal that both the Builders and the War Fighters came to be on. This allowed the War Fighters to demand new weapons again and again. The Builders actually became quite safe from the destruction that the War Fighters carried with them, as the War Fighters finally realized that the Builders will build for the sake of building, and destroying them as they destroyed rival War Fighters would eventually cause scientific and engineering progress to halt entirely. That, of course, would equal no more weapons, and that was unthinkable.
The Builders vary in size and shape more than the War Fighters, their form depending on the type of science they become interested in as they develop their understanding of reality. Despite the variations in between each Builder, they do conform to having at least more than twenty limbs of varying function, at least 10 different visual sensors of varying type evenly spaced around rotating modules to allow for high-speed scanning of whatever they decide to look at, and hardly any of them can move more than fifteen mph due to their need to stay in the one small area where they choose to live.
The Builders didn’t develop their space travel technology for a long time because they felt they had all they needed on their humble little planet and they worried that the War Fighters would start touching their stuff, attempt to try to figure out where they went, and generally be a worse nuisance than they already were. And so the War Fighters continued to abuse the Builders as they amassed an ever-increasing number of powerful weapons and tools for their near constant wars.
After several thousand cycles, much to the surprise of the Builders, the War Fighters actually started to make friends and form alliances between themselves, forming rules under a rather simple understanding of equal punishment for unlawful actions like killing each other and deceiving each other. Naturally, this particular group fared much better than most of the other groups and eventually, they made more friends and conquered most of their world. Soon, however, they came to a moral predicament in one of their argument sessions: Why would the Builders provide weapons to them if they knew what they were doing with them all those years? In accordance with their laws, they went to the nearest builder unit and confronted them with the question, to which the Builder responded, less than tactfully, “It wasn’t us who used the weapons to dismantle each other. We just did as we were asked.”
The War Fighters took exception to that.