ReachReach is a static ability.
A creature with flying can’t be blocked except by creatures with flying and/or reach. (See rule 509, “Declare Blockers Step,” and rule 702.9, “Flying.”)
Multiple instances of reach on the same creature are redundant. (CR 702.17)
Whenever this creature deals combat damage to a creature, 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 that creature.
Whenever you put one or more -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) on a creature, each opponent loses 1 life and you gain 1 life.