Truefire Paladin

The math is the whole pitch: two open mana turns the body into a 4/2, four open mana makes it a 4/2 first striker, and the activations keep stacking for as long as you have untapped lands to feed them. Vigilance means the swing does not cost you a blocker, so mana you sink into the attack still buys defense on the crack-back. The design lineage runs straight through firebreathing creatures like Shivan Dragon, but splitting the dial into two separate costs (one for size, one for first strike) makes every combat a granular calculation rather than a single throttle: you decide how much you want to clear, and whether you want to win the exchange before damage lands. The catch is the gold cost on both abilities. Demanding per activation rather than a single generic mana is what keeps the engine from snowballing on curve, since each pump requires both colors at once and eats through your untapped lands in a hurry. That tension (a cheap two-drop whose ceiling is gated entirely behind perfect mana) is the cleanest version of the aggressive mana-sink Knight: a creature that asks nothing of your deck except that you tap out and that your lands cooperate.