Yes, she MIGHT have, but there's no evidence that she did (outside of the amassed records and science teams at her disposal). If you're going to use this to support the idea that the Ascians are involved in Garlean affairs, you need direct evidence, and Nael working with the Ascians has never even been kind of implied.
But that's...not what the discussion was about? I didn't say anything about who was primarily responsible for Ultima. You were using Gaius' involvement with Lahabrea to suggest that the Ascians were manipulating Garlemald behind the scenes, which in turn was being used to suggest that Garlemald couldn't be blamed for their actions. I disagreed; as Gaius was rogue at the time, it's evidence of nothing other than his own desperation.
We do know that the Ascians are keeping an eye on Garlemald, but certain pieces of dialog actually imply that their approach is entirely hands-off - an offhand, unconcerned remark about them "playing their part." They clearly fit into the greater Ascian scheme, but if the Ascians were directly involved their affairs and governance, don't you think we'd have at least gotten a hint of it? And then, of course, there's the very direct claim made by Yoshida that the Ascians are going to play a much smaller role in 4.0 - which, incidentally, is a story that will bring Garlemald back to the forefront. If that isn't evidence against Ascian manipulation in Garlemald, I don't know what is.
