Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - Help/Tips/Tricks Backstab vs abilities

I actually just did it with both Sawtooth knife and Mortal blow.
They both showed critical damage increase when in the back.

I only tried each once so there are damage variance but we can clearly see the backstab does affect every skill.
Sawtooth Knife Regular: 86
Sawtooth Knife Backstab: 190

Mortal blow Regular: 462
Mortal blow Backstab: 1031

That's pretty clear to me.
(I had a 215% crit damage main hand)