Penance

A defensive engine built entirely out of inevitability: as long as your hand holds cards, you cannot be burned out by black or red damage. The cost is the wrinkle that defines it. Each prevention shield asks you to bury a card on top of your library rather than discard or pay mana, so the deck is paying in tempo and card-flow, not resources spilled to a graveyard. That recycled card draws right back, which means against a slow burn or attrition strategy a single Penance can theoretically blank an entire opposing game plan, one source at a time. The choice mechanic keeps it honest, though: choosing a source is not targeting, so it sidesteps hexproof and shroud entirely, but each activation names one black or red source and prevents only that source's next instance of damage this turn. A board of multiple attackers or a fistful of burn spells forces you to fire the ability repeatedly, slamming your library shut card by card. It is a hatebear in enchantment form, deliberately narrow (two colors only, no answer to blue, green, white, or colorless), built to invert a specific matchup rather than tax the table. Exodus was full of these pointed, asymmetric answers, and Penance is among the purest: a wall against exactly two colors that does nothing at all against the rest, and asks you to mortgage your draw step to hold it up.