Grey Knight Paragon

Flash on a removal creature changes the math entirely: this holds up as a combat trick that answers an attacker and leaves a 4/4 behind, so an opponent who swings into open white mana is choosing to trade their threat for a two-for-one. The Rites of Banishment trigger targets an attacking creature specifically, which is the restriction that keeps a five-mana body honest; it cannot preempt a threat on your own turn or clear a blocker, only punish the aggressor once the attack is declared. The Demon clause is the flavor made mechanical, upgrading destroy to exile against the sort of thing a Grey Knight was built to hunt, and it doubles as a genuine functional gap: the difference between destruction and exile is what separates this from ordinary spot removal against recursive or death-triggered Demons. What the card really wants is a defensive posture, a player content to sit behind untapped mana and turn every declared attack into a losing proposition for the other side. The white flash-blink lineage has long chased this kind of tempo swing (Restoration Angel and Flickerwisp trade in the same instant-speed surprise), but pairing the ambush with a mandatory removal trigger tied to combat makes this a wall that fights back rather than a value engine.