Azgh`rhga "lord of shadow"

Lifelnck, flaying, Swampwalker, hex proff
When Azgh`rhga, lord of shadow enter to the batlefield, each oponent must sacrifese a creature with power equal to {x}. You gain life equal to taht creature`s power.
If Azgh`rhga, lord of shadow werer send to the graveyard form any surse you must sacrifise any creature with a "pact of shadows" insted of destroing Azgh`rhga, lord of shadow.