The Illumidas are a hostile humanoid sentient species featured in the Arcadia of My Youth series.
The Illumidas are generally very human-like including their height, size, and physical features but their skin color contains a light shade of green. Eyebrows of the men are connected to their hair.
The Illumidas follow a very militaristic code to its most extreme, making them very hostile towards others; conquering many worlds and annihilating planets that do not surrender to them. Most Illumidas have a lot of pride to what attaches to them the most, for military leaders it is their merits and for scientists it is their creations often captaining the ships they have created.
The Illumidas function as an entire military nation, traveling the universe to dominate and eliminate any other party without mercy. They are mainly male oriented and as such women do not hold significant ranks and are considered second-rate. Much like the Mazon, they often made these conquered people into slaves with women often being made into sex slaves. When hiring mercenaries, they are often treated as cannon fodder. Those who do not comply with the ruling Illumidas bodies are often massacred such as the Tokaga people and even destroyed entire planets to prevent rebel uprisings.
After conquering worlds, figurehead leaders are often stationed on those worlds to prevent rebellions and often use campaigns to lower the local's dignity. However there are a few figures who deviate from the central army such as Zeda, who in his occupation of Earth made a more flexible rule due to disliking his homeworld. However, these rules while less harsh than others are still brutal which lead to a rebel movement lead by Maya and Emeraldas.
The Illumidas are an advanced race with many of their machines resembling insects including a dragonfly-like fighter the size of the Arcadia and cockroach-like tanks housing a lot of fire power. All ships are capable of space travel and are armed with with missiles and beams capable of fighting evenly with entire fleets. All weapons on the ships are automatic, as such they all have a weakness when it comes to ammunition as they are often depleted quickly when it battle, leaving them as little more than transporters.
The Illumidas during an unspecified time began expanding their empire conquering many worlds. Eventually they come upon Earth. For a length of time, Earth's military forces managed to fight against the Illumidas threat until their forces were overwhelmed with Earth under their control. Supporters had even gained a place on Earth's dominion. Three exiles of the planet: Harlock (S-009999), Tochiro Oyama (S-009998), and Emeraldas (x-00001) however continued to resist the Illumidas, each with reasons of their own whether personal or based on beliefs. As such they were continued to be hunted down but could never be caught.
The three's actions had ended up costing the Illumidas many resources and personnel one of which was Zeda. Because of this, Mr. Zone completely acknowledged the threat of these individuals, particularly Harlock. Harlock would eventually lead an attack on the Illumidas' home base, destroying it and forcing the Illumidas to scatter while releasing their hold on Earth.