I've been going through my comic collection, trying to clear out stuff as I do from time to time. I was up to Tony Bedard's R.E.B.E.L.S. run, and I was rereading the Blackest Night tie-ins, when something struck me. At that point, Vril Dox' kid, Lyrl, has his 12th-level intellect back, and has thrown in with Starro the Conqueror. Vril has figured the best way to get rid of the Undead Lanterns that were coming after him was to sic them on Starro, and Starro's quite enjoying fighting an enemy he can't manage to kill. Meanwhile, Lyrl's trying to come up with some weapon that can mimic that particular energy emitted by a Lantern's ring, since that's all that can destroy these things. But nothing he builds works.
So, like the title of the post says. Coluans are supposed to be about the smartest species in the universe, and Lyrl is exceptionally smart even by their standards (Brainiac 5 is listed as a 12th level, so the only one I know for sure as being smarter is the original Braniac, who was listed as being some degree greater than 12th-level, meaning they can't accurately gauge it, I guess). It's not like one has to come up with a power source, the rings run off the emotional spectrum or whatever, the ring just has to tap into that. I know, I make it sound easier than it is, but come on, the Guardians managed it.
OK, they're a really ancient race (of little twits), they had a long time to study the emotional spectrum, figure out how to build something you can control mentally that runs off willpower, and they don't share their work. So unless a Coluan is brought into the Corps (which must have happened at some point), Colu doesn't get to study a ring, so they have to work off whatever they can observe at a distance. Even so, the Qwardians were able to cook a yellow ring up for Sinestro, and it didn't seem inferior to a GL ring. So they're smarter than the Coluans? Or is this a case where they're "Weaponeers", so they possess some limited brilliance that only expresses itself when they make weapons? Still, I wouldn't think that would somehow restrict the Coluans from figuring it out. They certainly possess sufficient understanding of the universe to make all sorts of interesting weapons.
Maybe it's supposed to be the emotional aspect that escapes them. They can't figure how to measure or quantify emotions, so they can't devise a weapon that absorbs and controls an energy they don't understand. Except the Guardians divorced themselves from emotions, didn't they? I guess it's a question of whether they did that before or after they made the rings, or maybe the Manhunters, since they ran on the same power source as the rings. Though the Guardians don't have to use the rings, so it wouldn't matter if they can't or won't feel anything, because they find others to handle that part. The Coluans would have to rely on themselves (I can't see them making power rings, then being dumb enough to hand them to some other species to use), and maybe that won't work. So it's considered a dead end field. Which doesn't explain Lyrl's failures, except if it was strictly a matter of time. He only had a couple of days.