Okay so... I watched Biohazardia's video on questions answered by Tui at Boskone about Wings of Fire, and something she said blew my mind.
She asked Tui what could've possibly made the bright, happy futures Clearsight saw of her and Darkstalker possible, because they had to have been possible in some way if she saw them.
As it turns out, well... I'm actually kinda shocked I hadn't figured it out myself because when I think about it, there were subtle hints made through dialogue about it all over the Darkstalker Legends book.
And guess what? If you're reading this right now and want to know what it is, I won't tell you until tomorrow or the day after that or something, lol.
So for now just read all the dialogue in the book (especially the ones said by Fathom and Clearsight) and try figure out what might've made him listen to Clearsight.
Hint: It's an animus enchantment.
Also: I posted this at 12:00am my local time, so extra day gone by.