The shade passive ability backstab does not really have a lot of info on what is considered a backstab.
There’s a sound when you get it right, but it would be nice if there was some in game way to test if your doing it right.
Perhaps a dummy in the keep with a face painted on one side that only takes damage if you the the angle right. or even just has a visual indicator of where you need to hit like a face painted on one side with a black/red area on the other side. (Feels like something the elf might do after seeing all the coins pinned to the wall in verms 1.)