CovenAn ability word has no rules meaning of its own. It groups abilities with similar themes; the text following it explains this card’s effect. (CR 207.2c) — Choose target creature you control and target creature you don't control. If you control three or more creatures with different powers, put a +1/+1
counterTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) on the chosen creature you control. Then the chosen creatures
fightA spell or ability may instruct a creature to fight another creature or it may instruct two creatures to fight each other. Each of those creatures deals damage equal to its power to the other creature.
If one or both creatures instructed to fight are no longer on the battlefield or are no longer creatures, neither of them fights or deals damage. If one or both creatures are illegal targets for a resolving spell or ability that instructs them to fight, neither of them fights or deals damage.
If a creature fights itself, it deals damage to itself equal to twice its power.
The damage dealt when a creature fights isn’t combat damage. (CR 701.14) each other. (Each deals damage equal to its power to the other.)