What is the relation between the Mor-Taxans and Morthrens?

In season 1, the aliens that were re-animated from the 53 invasion were aliens from a planet called Mor-Tax. They were very insect looking, with three arms and three fingers. And they even saw everything in three. They somehow merged inside human bodies to avoid detection.

In season 2, the aliens came from Morthrai and they looked humanoid and cloned people instead of taking over human bodies. They wipe out the Mor-Taxans and take over the invasion. Which leads to one question, what was the relationship between the Morthrens and Mor-Taxans.

Were they the same race which evolved differently because they were on different planets? Or are the Mor-taxans a conquered slave race which serves the Morthrens? In the season 2 episode "Seth of Emun", during a flashback sequence, we see the Morthrens using Mor-taxans to attack the planet of Emun, so were the Mor-taxans a warrior race that did the Morthrens bidding? That god like thing the Morthrens worship, The Eternal One, looks more like a Mor-Taxan then a Morthren, so, there is some connection between the two races.

I know they used different type of technology. The Mor-taxans used those gold ships with the heat ray and skeleton beams, in one season 1 episode, they had a little boomerang looking thing which shot the skeleton beam. The Morthrens, otoh, had this little green orb which shot a green a fast green laser which disentegrated whoever it touched.

When the Mor-taxans died, they dissolved into a puddle of goo. When the Morthrens die, they shriek out as they bleed out some shiny green blood, their skin dissolves inward, and then they dust away like some vampire. Unless they explained it and I don't recall, I don't think they ever explained how the Morthrens and Mor-Taxans were related or connected to each other. So, what do you think was the connection?