Hey @idso not sure if someone else already answered you, but the cat would be Millicent. Pablo Hidalgo (one of the writers) made a joke once about Hux’s cat Millicent using Kylo’s ash pile thing from TFA as a litter box. Predictably, the kylux fandom latched onto it and she has since been featured prominently in both fic and art, regardless if it’s canon verse or an au
Tbh there’s a lot of oddly specific stuff in this fandom in general and there’s a few guides floating around, but here’s a really good starter. If you’re new, I recommend reading it as it might help explain some things that likely don’t make sense if you haven’t been here for the last 2 years lmao. Also I’ve been stuck here for 90% of it, so I’m happy to answer any questions you or anyone else who’s new to the fandom might have ^^
