the front side of Keiga, the Tide Star
the back of a classic MtG card
the front side of Nim Deathmantle
the back of a classic MtG card
the front side of Pitiless Plunderer
the back of a classic MtG card
the front side of Phyrexian Altar
the back of a classic MtG card

Color Identity: U, B

Initial Card State

  1.  All permanents on the battlefield.

Steps

  1. Whenever an opponent controls a creature, activate Phyrexian Altar by sacrificing Keiga, adding one generic mana.
  2. When Keiga dies, it, Pitiless Plunderer and Nim Deathmantle trigger.
  3. Resolve the Pitiless Plunderer trigger, creating a Treasure artifact token.
  4. Resolve the Keiga trigger, causing you to gain control of a creature an opponent controls.
  5. Activate Phyrexian Altar by sacrificing the creature you gained control of in step 3, adding one generic mana.
  6. When the creature dies, Pitiless Plunderer triggers, creating a Treasure artifact token.
  7. Activate the Treasures by tapping and sacrificing them, adding two generic mana.
  8. Resolve the Nim Deathmantle trigger from step 2, causing you to pay four generic mana to return Keiga from your graveyard to the battlefield, and attach Nim Deathmantle to it.
  9. Repeat as desired and/or whenever a creature enters the battlefield under an opponent's control.

Results

  1. Gain control of all creatures opponents control and sacrifice them.
  2. Gain control of any creatures that enters the battlefield.
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