Irea, Brewer of Life and Death

As an additional cost to cast Iria, Brewer of Life and Death, pay 2 life or let target opponent gain 2 life.
Whenever an opponent gains/loses life, add {w},{b}, or {g} to your mana pool.
Whenever you gain/lose life, put a +1/+1 counter on Iria, Brewer of Life and Death.
"Life and death are at my fingertips."