Serene Steward

A lifegain payoff built around a throttle rather than a floodgate. The trigger is wide open (any instance of life gain, from any source, fires it), but each conversion costs a white mana, and that payment is what tethers a potentially runaway engine to a real resource. Note the unit: the ability triggers once per instance of lifegain, not once per life point, so gaining three from a single lifelink hit yields one trigger and one counter, not three. That distinction is the ceiling. What scales the card is the frequency of your lifegain events and the depth of your mana pool, not the size of any single gain: a steady drip of soul-sister-style triggers off small creatures entering feeds it far better than one fat lifelink swing. The targeting is more flexible than the lifegain-counter theme usually allows, too, since the counter lands on any creature rather than only this one, letting you concentrate growth on a single threat or spread it across a board. It belongs to a lineage of cards trying to make lifegain do something on the battlefield instead of padding a number that rarely decided games, and it does that by binding two resources together: the life you gain and the white you can spare to convert it. The 2/2 body is just a vessel; the value lives entirely in that conversion rate, one white mana at a time.