Xalchion

Doublestrike.
As an additional cost to cast Xalchion you may
pay any amount of life. Xalchion costs {1} less to cast for each 2 life you pay in this manner.
Pact - Xalchion deals damage to you equal to its power. (At the beginning of your upkeep, pay Xalchion's pact cost. If you can't, sacrifice
Xalchion.)