The Time of Life

Enchantment - Saga

: You gain 3 life

: Create two 1/1 white soldier creature tokens.

: Exile this Saga, then return it to the battlefield transformed under its owner's control.

The Time of Death

Enchantment - Saga

: Each Opponent loses 3 life.

: You may sacrifice a creature. If you do, draw a card.

: Exile this Saga, then return it to the battlefield transformed under its owner's control.

Create a Blue Demon with a downside that is on-flavor for the color, and a matching upside.

Promise of Eternity

Enchantment

Each Creature in your graveyard with power less than your devotion to black has Unearth. Its unearth cost is equal to its mana cost plus .

If your devotion to black is 8 or more exile ~ then return it to the battlefield transformed under your control.

"Who doesn't want to live forever?"

The Eternal Halls

Land

: Add . You may spend this mana to cast a creature from your graveyard. If you cast a spell this way, it becomes an artifact and loses all other card types.

Continue the cycle. We've still got Blue, White, and Green.