Blue thread. Now that was certainly something fascinating. Tsukasath wondered what it meant, if it meant anything at all. He'd never been hurt by thread before, the general lack of marks on his body and Yermie's own thoughts could confirm that well enough, so he couldn't say for sure if it worked differently than regular thread, burned differently, consumed differently.
Regardless, something had clearly changed in the nature of thread. It warranted investigating. But thread was dangerous. He couldn't risk Yermie being hurt in the pursuit of this knowledge. And while he briefly flirted with the idea of coaxing Ogatath and Daphne to look into it, Yermie would be devastated if anything happened to Daphne. Also, Ogatath wasn't the brainless thug he liked people to think he was, and there was a chance he'd grow suspicious if Tsukasath tried to coax him into it too hard.
So Tsukasath had been on the lookout for a likely candidate to convince to trying flying high enough to see where thread came from. They couldn't be too cautious or sensible, least they immediately give up on the idea, but he didn't want them too stupid, either. After all, they'd need to be able to think for themselves once they got into the air. A dragon with more stamina than speed might also be preferable, and so through careful observation of the dragons and their riders around Fort, he think he had a pair who'd do nicely: Adelais and Katzenjath.
He approached the garnet one day in the Weyrbowl while riders were having their midday meal. Good day to you, Katzenjath, he said politely. I trust you are well? That recent threadfall certainly was unusual, wasn't it? I hope you and yours weren't too badly injured during it? He hadn't needed to play up the limp from the thread scoring on his right foreleg; it was still fresh enough that putting weight on it was uncomfortable.