Venerable Knight

The trick this one-drop pulls is making its own death the payoff rather than the cost. A 2/1 for one mana is a genuine early attacker, the kind that trades with two-drops in the opening turns, but most such creatures become dead weight the moment the opponent stabilizes at a higher toughness. The death trigger inverts that math: every trade leaves a permanent counter on a surviving Knight, so a board that keeps getting chipped away is a board that keeps growing. That is what lets a wide, cheap Knights curve stick to its game plan without running out of gas: the bodies you lose in combat feed the ones still standing, and the counter lands on whichever Knight most needs the size. The trigger keys specifically on dying, though, so the reward is contingent on the card actually reaching the graveyard from the battlefield; a removal spell that exiles it, or a bounce back to hand, cuts off the growth entirely, which shapes how each answer trades. The counter is the restriction that keeps the rate honest, too: it needs another Knight in play to land, so this rewards being cast early into a board already committed to the tribe rather than dropped as a lone body. The structure favors a low, aggressive curve over a top-heavy one, and it reads as a plain beater right up until you notice that dying in combat is the intended line, not the failure state.