Hi there! I’m so sorry for the 2 month late reply, I’m ashamed to say I never saw or read this ask, and only saw it due to another message that I received just now. I’ve edited the rec post and will be reblogging it again. My sincere apologies, especially for how late I got to this, and especially for never realizing in the meantime.
The fic is here, by @outer-planets-alliance.
I Am More Than My Scars
Summary: Grand Marshal Hux is distraught when he discovers what kind of training Supreme Leader Ren is engaging in to keep himself bound to the dark side, and suspects the involvement of the deceased Snoke.
(sidenote: I recall reading this at the time and loving it. Not including it on the rec-list is purely my fault, but I cannot recommend this enough for the lovely writing and the sense of intimacy between Kylo and Hux- I kept on thinking about it for days. Revisiting it again today, it’ll no doubt stick in my mind again. If you’re still following this blog, I definitely recommend you give it a shot if you haven’t already!)