Huh?
I def. empowered it in the past - even before CP existed. I mean it's like Inner Death was made with Empowered Strikes in mind (or the other way round).
But to be sure I tested it again 5 minutes ago. No mods, new char, new playthrough: Inner Death + Empower in the vanilla game works fine for me. See the little vid I made just now:
Maybe this is your problem with Empower + Inner Death: one cannot empower any ability that got added with the console. Instead you have to level up manually and pick the ability that way. Then you can empower said ability (if it works with Empower in the first place). I just give the char in question enough XP to level up to 20. Then I set their class level to 19, do the last level-up manually and pick the ability I want to test with Empower.
Yeah, I also eyed Vrer Chiora and Mouth Char. They should stack just fine bc. one is universal crit dmg and the other weapon dmg. Will test later...