With the Wraith’s card Combat Stance it says the first time she is dealt damage she deals two melee damage that target. So if you reduce the damage something will deal to you to zero for example Voss’s 2 fire damage to the lowest hp does she get dealt zero damage and hits him or does she just not get dealt damage and nothing happens?
If you’ve reduced the damage, like with her innate power, enough that it is reduced to 0, then she isn’t actually damaged and the power on Combat stance won’t trigger.
If she’s reducing by 2 and gets hit for 4, then those other 2 points would slip through and deal The Wraith damage, triggering Combat stance and letting her hit whoever hit her.
Yup, what Tamar said is totally correct. Damage is only actually dealt (and only actually triggers things that happen when damage is dealt) when a target loses HP.