X can't be 0.
Draw X cards. Create an X/X black Demon creature token with flying. Your life total becomes X. You can't gain life for the rest of the game.

Whenever Verdant Dread or another permanent you control named Verdant Dread enters, manifest dread.
: Conjure a card named Verdant Dread onto the battlefield. Activate only as a sorcery.

Flying
When Mangled Soulrager enters, switch the power and toughness of each creature on the battlefield. You get a twelve-time boon with "Whenever a creature you control enters, switch its power and toughness."
Cycling

When Ethrimik enters, manifest dread.
Other creatures you control get +1/+1.
As long as you control another creature, Ethrimik can't attack or block.

Impending 3—
Whenever Lurker in the Deep enters or attacks, seek a nonland card.
Whenever you seek one or more cards during your turn, conjure a duplicate of each of those cards into your hand, then manifest those duplicates.