Demonic Rising

At the beginning of your end step, if you control exactly one creature, create a 5/5 black Demon creature token with flying.

Awoken Demon

Ecstatic Awakener

{2}{B}, Sacrifice another creature: Draw a card, then transform Ecstatic Awakener. Activate only once each turn.

Ecstatic Awakener // Awoken Demon

Liesa, Forgotten Archangel

Flying, lifelink
Whenever another nontoken creature you control dies, return that card to its owner's hand at the beginning of the next end step.
If a creature an opponent controls would die, exile it instead.

Fallen Angel

Flying
Sacrifice a creature: Fallen Angel gets +2/+1 until end of turn.

Demonic Appetite

Enchant creature you control
Enchanted creature gets +3/+3.
At the beginning of your upkeep, sacrifice a creature.

Demonic Embrace

Enchant creature
Enchanted creature gets +3/+1, has flying, and is a Demon in addition to its other types.
You may cast Demonic Embrace from your graveyard by paying 3 life and discarding a card in addition to paying its other costs.

Angel of Despair

Flying
When Angel of Despair enters, destroy target permanent.

Shattered Angel

Flying
Whenever a land an opponent controls enters, you may gain 3 life.

Demonic Gifts

Until end of turn, target creature gets +2/+0 and gains "When this creature dies, return it to the battlefield under its owner's control."

Meditation Puzzle

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
You gain 8 life.

Teferi's Puzzle Box

At the beginning of each player's draw step, that player puts the cards in their hand on the bottom of their library in any order, then draws that many cards.

Herald of Torment

Bestow {3}{B}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying
At the beginning of your upkeep, you lose 1 life.
Enchanted creature gets +3/+3 and has flying.