It's been a long time since I saw Thirdspace. I'm seeing stuff in wiki and elsewhere online saying the thirdspace aliens once actually mind-dominated some Vorlons. I don't remember that from the movie being explicitly said anywhere. Does anyone recall for sure? Not books, just the movie.
Anyway, I wish more had been done with them than just that movie. Some flashback scenes of their first incursion would have been great. I mean them breaking through/coming through the gate, encounters with different First Ones, mind-controlling Vorlons (wow!), their eventual ejection by the Vorlons shutting down the gate (how did that work again, I mean that first casting out?). Thirdspace aliens having first meetings with the Shadows...possible thirdspace/Shadow alliance (yah that'll last long but would be fun).
Might have to do a rewatch. Well what the hey.