Sunstar Lightsmith

The trigger deliberately skips your opening play and rewards the follow-up, and that off-by-one is the whole design. Paying off your first spell would pay off casting a spell, which every deck does; demanding a second one each turn forces a curve dense enough to double-spell reliably, and it promotes cheap interaction and cantrips from filler into engine fuel. Each qualifying turn advances two clocks at once: a card toward your grip and a +1/+1 counter toward a body that stops trading down and starts trading up. Because the counter is permanent, a Lightsmith left alone across a few double-spell turns quietly grows into a real threat while it refills your hand, which is the tension a defensive answer has to resolve: spend removal now and eat the tempo cost of killing a 3/3, or let it snowball and lose the long game. White has historically leaned on flat card advantage through enchantments and enter-the-battlefield value; folding the draw into a casting cadence pushes the color toward a tempo-tuned engine that wants a low, redundant curve rather than a pile of expensive haymakers. The reward is generous enough that the real deckbuilding question it poses is not whether you can meet the trigger but how you guarantee the pair of spells every turn without watering the deck down into cantrips that do nothing else.