Archangel of Strife

Flying
As this creature enters, each player chooses war or peace.
Creatures controlled by players who chose war get +3/+0.
Creatures controlled by players who chose peace get +0/+3.

Commander Anthology

Flying
As Archangel of Strife enters the battlefield, each player chooses war or peace.
Creatures controlled by players who chose war get +3/+0.
Creatures controlled by players who chose peace get +0/+3.

From the Vault: Angels

Commander 2011

Archangel of Strife's bonuses apply immediately. Depending on your choice, Archangel of Strife will enter as either a 9/6 or 6/9 creature.

Archangel of Strife's second and third abilities are linked. Similarly, its second and fourth abilities are linked. The bonus a player's creatures get depends only on the choice that player made when Archangel of Strife entered.

As soon as Archangel of Strife leaves the battlefield, the bonus stops applying. If it returns to the battlefield, players will be able to make new choices.

If there are two Archangels of Strife on the battlefield, and you choose war for one and peace for the other, your creatures get +3/+3.

The active player chooses war or peace first, followed by each other player in turn order. Each player will know what previous players chose when making their choice.