Ageless Sentinels

A 4/4 flier nailed to the back rank, built to swallow attackers and never swing back. The transformation is the whole design: declare a block and the Wall becomes a Bird Giant, permanently shedding Defender. The conversion is one-directional but not strictly additive the way it first reads; the loss of Defender is real, and the creature stops being a Wall, but everything that mattered (the 4/4 body, the flying) survives the change. The result is a defensive piece that an aggressor's own attack turns into an offensive one. The timing is the clever part. The trigger keys off the block declaration, not combat damage, so it fires whether or not the blocked creature dies, and the change sticks: one block flips the role permanently. The catch is that the controller cannot pull the trigger alone. Blocking demands an attacker, and a wary opponent can simply decline to swing into it, leaving a 4/4 flier that holds the air and the ground but never converts. So the upgrade is gated behind a decision the other player owns: attack and hand over a creature that now closes games, or stall and let the wall sit there doing nothing but blocking. It is an early take on the role-flipping creature, the body you built around defense becoming the body you win with, an idea later designs returned to with more frequency than this quiet version ever earned.