Hi, I just signed up to comment on this thread, I'm using a translator.
As someone who's had the same problem, I've scoured all the communities and figured out how to keep Yenna and their cat Grub alive:
(Also, I've implemented it and successfully saved them both)
1. Include Halsin, Gale in your party and leave Lazael in the camp.
2. meet with Gotash and Listen to his warnings about shape-shifter.
(If you've already met Gotash, this may be a trial-and-error situation; it's wise to revert to your save).
3. Never stop by the Elfsong. It will trigger a forced kidnapping.
4. Avoid Elfsong and descend into the sewers another way. Take a long break after entering the sewer.
The fastest passage is the manhole under the Arch by the Basilisk gateway.
5. Lazael tries to kill Yenna, saying she has 'found the shapeshifter'; stop her with persuasion/threats
? Lazael turns into Orin, then leaving Yenna and the cat alive.
I had to take 4 long breaks after going into the sewers due to two events.
In the end, I went back to 3 hours of saves to save Yenna and Grub, but I don't regret it.
I hope this works for you as well.
