Honestly I'm kind of endeared that Caiatl didn't go to war with the Imperium until the Tharsis attack. I'm sure there were tensions between them & maybe the massacre simply pushed them past boiling point, but it also kinda shows that she really does value us as allies. Or maybe she has lightbearers she really cares about. Maybe both
(Sidenote. Does Barant mean anything?)
Yeah, I also really enjoy that. I think that Caiatl absolutely perceives a direct attack on the Lightbearers as an attack on herself as well. And in a way, it's true, as Caiatl is part of the Coalition with the Vanguard and the Lightbearers. And she definitely has Lightbearers she personally cares about as well, primarily probably based on the fact that she works with Lord Saladin who is a part of her council, and she's definitely close to the Vanguard as well.
Barant does mean something! It's mentioned at the start of the campaign:
Eris: This “Barant Imperium” and their panoply are like no Cabal we’ve encountered. How did they rise so quickly? Eido: Caiatl’s Battlenet references “Barant” as the Legionary species. No other data…
It's also mentioned in the lore book (pages that still aren't around on Ishtar), from page 8 (Entry 5 - A Conduit for All Futures):











