There will be two types of relics: offensive relics and Defensive relics.
The offensive relics work like they are now: they increase a certain offensive stat when you cast certain spells. But instead of luck/anger, I think you can get relics for each stat that you want.
For denfesinve relics, they will give a permanent bonus to a defensive stat, and, most likely, you'll be able to get defensive relics for each of the defensive stats.
Regarding the relics that you get from the Battleground vendor, the defensive relics will give Willpower and the offensive relics will give anger on certain spells.