After mere months of existence, the so-called "Machine War" spilled over D'Jarex Iota's borders and into the rest of the galaxy.
A few detachments from both sides were tasked with laying claim to any uninhabited world they ran into, while the main fleets sailed in the general direction of the Orion arm, in an effort to find the rumored home-world of the D'Jarex Iotians' ancestors (well, the D'jarex Iotians did, the portion of Marendex's forces that weren't busy colonizing the rest of the galaxy were just doing their best to keep an eye on the enemy).
What they found was not the near-dead ball of rock that they were expecting, but instead the single most heavily fortified planet in the galaxy. Whole fleets of ships raced from all corners of the Solar System to impede the advancing foreign forces.
General Maxxim's fleet managed to punch a whole in the blockade first, and successfully deposited a small group of carefully-selected agents on the surface, before quickly retreating.
After a few months of alliance-building, bribery, smuggling, and who-knows-what-else, these agents eventually managed to gather enough parts, money, and workers to begin assembling a weapon that would do-in those stubborn machines once and for all.
Named after Marendex's legendary adversary, Mardon: the Lord of Chaos, this new weapon would surely lay waste to all who opposed it.