Evra, Halcyon Witness

Lifelink
{4}: Exchange your life total with Evra, Halcyon Witness's power.

Cradle of Vitality

Whenever you gain life, you may pay {1}{W}. If you do, put a +1/+1 counter on target creature for each 1 life you gained.

Enchant creature
Enchanted creature has "Whenever you gain life, put that many +1/+1 counters on this creature."

Defender, flying
At the beginning of your end step, you may gain life equal to the power of target creature you control.

Sacrifice Children of Korlis: You gain life equal to the life you've lost this turn. (Damage causes loss of life.)