You can activate one of Ajani, Nacatl Avenger's loyalty abilities the turn he enters the battlefield. However, you may do so only during one of your main phases when the stack is empty. For example, if Ajani, Nacatl Avenger enters the battlefield during combat, there will be an opportunity for your opponent to remove him before you can activate one of his abilities.

You don't choose a target for Ajani, Nacatl Avenger's second ability when you activate it. Rather, if you control a red permanent other than Ajani, Nacatl Avenger, a second "reflexive" ability triggers when you create a Cat Warrior creature token this way. You choose a target for that ability as it goes on the stack. Each player may respond to this triggered ability as normal.

If an opponent doesn't control any permanents of one of the types, they'll still choose the permanents of the types they do control.

When Ajani, Nacatl Avenger's last ability resolves, starting with the next opponent in turn order, each opponent in turn order chooses permanents they control. Each opponent will know the choices made by players who chose before them. They then sacrifice all of their unchosen nonland permanents simultaneously.

In the Commander variant, a double-faced card's color identity is determined by the mana costs and mana symbols in the rules text of both faces combined. If either face has a color indicator or basic land type, those are also considered. For example, Ral, Monsoon Mage's color identity is blue and red, since its front face is red and its back face has a blue and red color indicator.

Lands can't be chosen and won't be sacrificed, even if they have any of the types referenced by Ajani, Nacatl Avenger's last ability.

Each face of a transforming double-faced card has its own set of characteristics: name, types, subtypes, abilities, and so on. While a transforming double-faced permanent is on the battlefield, consider only the characteristics of the face that's currently up. The other set of characteristics is ignored.

In some rare cases, a spell or ability may cause Ajani, Nacatl Pariah to transform while it's a creature (front face up) on the battlefield. If this happens, Ajani, Nacatl Avenger won't have any loyalty counters on him and will subsequently be put into his owner's graveyard.

A permanent with more than one type may be chosen as any of its types. For example, an artifact creature may be chosen as the artifact, the creature, or both. Choosing the same permanent twice this way has the same result as choosing it once.

A transforming double-faced card enters the battlefield with its front face up by default, unless a spell or ability instructs you to put it onto the battlefield transformed or allows you to cast it transformed, in which case it enters with its back face up.

The mana value of a transforming double-faced card is the mana value of its front face, no matter which face is up.

Each transforming double-faced card in this set is cast with its front face up. In every zone other than the battlefield, consider only the characteristics of its front face. If it is on the battlefield, consider only the characteristics of the face that's up; the other face's characteristics are ignored.

In a case where you create more than one Cat Warrior creature token with Ajani, Nacatl Avenger's second ability (for example, because of the effect of Doubling Season), the reflexive ability will trigger once for each Cat Warrior you made this way. If a replacement effect causes you to create different tokens instead (for example, the effect of Divine Visitation), the creation of those tokens won't cause the reflexive ability to trigger.

The back face of a transforming double-faced card usually has a color indicator that defines its color. Colorless back faces, such as lands, do not.

If you are instructed to put a card that isn't a double-faced card onto the battlefield transformed, it will not enter the battlefield at all. In that case, it stays in the zone it was previously in. For example, if a single-faced card is a copy of Ral, Monsoon Mage, choosing to exile that permanent during the resolution of its triggered ability will cause it to remain in exile.