
When Ajani enters, create a 2/1 white Cat Warrior creature token.
Whenever one or more other Cats you control diedieA creature dies when it goes from the battlefield to a graveyard. Being exiled or returned to hand is not dying., you may exile Ajani, then return him to the battlefield transformed under his owner's control.
+2: Put a +1/+1 counter on each Cat you control.
0: Create a 2/1 white Cat Warrior creature token. When you do, if you control a red permanent other than Ajani, he deals damage equal to the number of creatures you control to any target.
−4: Each opponent chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest.
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Read from the rules text. A card that enables a keyword makes or is the thing; a card that rewards it gets better when you have it. Two cards interact when one enables what the other rewards.