Guardians of Koilos

A 4/4 for five is a fair blocker, but nobody plays this construct for combat: the enters trigger is the point, and the fencing on it is what makes the card specific. It cannot bounce anything; the target must be a historic permanent (an artifact, a legendary, or a Saga) you already control. That restriction converts a generically clunky reuse engine into a deliberate value lever for decks stacked with enters-the-battlefield triggers on artifacts and legends, or for re-chaptering a Saga before it sacrifices itself. Because the body has no flash, the whole package operates at sorcery speed, so this is a proactive engine, not a reactive one: you set it up on your turn to replay a value trigger or bank a threatened permanent, not to snatch something back in response to a removal spell. The "you may" is doing quiet work too: with nothing worth returning, the trigger lapses and the body simply lands, no feel-bad. What it answers is a small but recurring design problem: how to print permanent recursion that supports a synergy theme without opening a soft-lock loop with a sacrifice outlet or a free repeatable bounce of an opponent's artifacts. By walling the target off to your own historic permanents, the card keeps the upside while closing the abusive doors. It sits inert until you have the right thing to return, at which point the 4/4 becomes incidental and the bounce becomes the reason it is in the deck.