Well Since I am here I might as well post my artifact of death
THE WELL OF SOULS
This artifact contacts the souls of over 10000 souls over the years. It is a blood red diamond, the size of a mans fist.
When around a lich, death knight, or other creatures dependant on phylactaries, It can suck out the souls of them and prevent them from reforming with their phylactary.
Can take out the souls of any creatures that has one. Creatures must make a will save DC 30 or be trapped in the well forever. the reach for this is everything within a mile besides whatever is holding it.
Any creatures without their souls can now be controlled by the well. The well can use them as if they had the same class levels they had in life.
The well can also summon a very large amount of undead, say 1000 zombies skeletons or the like, this power can be used once per day.
The point is don't let the party get this.
The way this can be destroyed is it needs to be destroyed by a holy avenger, it has hardness 30 and 50 hit points.
The problem when it is destroyed is EVERY SOUL inside of the WELL is released!!!!!!!! Incuding those of several high level liches and death knights.