Prison Realm

White's exile-until-it-leaves lineage keeps getting refined, and Prison Realm is one of the tidier iterations, running the same Oblivion Ring and Banishing Light template with two deliberate narrowings that change how it plays. The exile can only touch what an opponent controls, so it cannot be turned inward to blink your own permanents or reset your own enters-the-battlefield triggers, closing a loophole older versions left open. And it hits only creatures and planeswalkers, dropping the "target permanent" catch-all that let Oblivion Ring answer artifacts and enchantments too. In exchange it staples a scry to the removal, a small piece of card selection that quietly makes the card feel better in a topdeck war even when whatever it exiled eventually comes back. The trade is coherent: you surrender the flexibility to answer anything and gain a clean, reliable answer to the two threat types white most wants gone. What it does not fix is the standing weakness of the whole cycle: the answer is crackable. The exiled permanent is not dead, only parked, and any enchantment removal frees it. When this leaves the battlefield, the exiled creature or planeswalker returns, re-triggering its own enters-the-battlefield abilities for its controller, so cracking it against the right target is closer to a value engine than a setback. What separates it from its ancestors is the discipline of the target line, not the power level.