The Overlords did join the Overmind.Just not the ones who serve the Overmind. As Karellen said they have become as advanced as they can and can go no further. The reason is But What About the Astronauts? See, Jan (book)/Milo (series) did not die with the rest of humanity because he was not on Earth. The Overlords on their home planet ascended to join the Overmind, but the ones on an offworld colony weren't there. You have to be on your home planet to ascend. The Overlords who joined the Overmind are the ones directing their distant relatives to do the Overmind's bidding. So the reason their "technology led them astray" was you need to join the Overmind before leaving your home planet.
- In the TV mini-series, if Rachel had lived, then she and Milo probably would have taken Karellen's offer to leave with him, rather than just Milo choosing to stay as the Earth is destroyed.
The "Devil" character in the Cantina in Star Wars is an Overlord.The one here. Before they started working for the Overmind. Heck, maybe the Overmind is The Force! Maybe the Overmind already cleared out that far away galaxy a long time ago after the Force was balanced! Maybe that's the only way to stop the Dark Side - not give anyone the chance to create a galactic civilization.
- Doesn't work. Devaronians don't have wings or tails.
- Yeah, but we don't see that in the film universe.
Overmind is actually a parasyte.Many parasitic wasps tend to find victims, immobilize them and placing larvae in them, which then grows and consumes its host. If you look at the event from this angle, Overmind might just breed it's offspring to expand itself, using civilizations as hosts. Overlords are there to help pacify and de-fang the victim civilization, so it couldn't resist, and wouldn't even wanted to. So there's no "ascension to a higher plane of existence", only murder. The Overlords directly state that, saying that "these children aren't yours".