One of the abilities of the artifact is to drain vitality and strength (Con, Str) when it deals damage. I want the players to have to roll a Con saving through or take some ability damage. Is there anywhere where someone had laid out the different saving throw DCs based on party level and how hard you want the saving throw to be for a quike graph or something?
You can probably get what you want out of the Monster Statistics by CR table, which includes typical DCs of their abilities.
thanks!