Death, the One End

Death touch, Devoid, Life link
Death, the One End may only be cast if there is at least one Reaper in the graveyard
As an additional cost to casting Death, the One End sacrifice one land
When Death, the One End enters the battlefield all other legendary cards on the battlefield are exiled
If another legendary card enters the battlefield, it is to be sacrificed
All Reapers cost one {w} and one {b} less