AfflictAfflict is a triggered ability. “Afflict N” means “Whenever this creature becomes blocked, defending player loses N life.”
If a creature has multiple instances of afflict, each triggers separately. (CR 702.130) 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
Whenever an opponent casts a spell, 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 this creature.
Whenever this creature deals combat damage to a player, remove all -1/-1
countersTo 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) from it.