Archangel Avacyn // Avacyn, the Purifier
Flash on a five-mana angel is what warps a turn of combat here in a way few angels ever have: an instant-speed 4/4 flyer with vigilance was already a serviceable ambush blocker, but the enters trigger converts it into a board-saving fog that also kills attackers, since your creatures gain indestructible while theirs do not. That alone justifies the slot. The transform trigger is where the design turns genuinely double-edged. Granting indestructible invites you to throw creatures into combat freely, but the moment one of your non-Angels dies, Avacyn flips on the next upkeep and deals three damage to every other creature and each opponent: a delayed sweep you do not always want to fire. The build asks you to weigh protection against detonation, and the timing window is unforgiving, because a sacrifice effect, a chump block, or an opponent's removal can trip the flip on a turn when sweeping your own board is the last thing you need. That self-inflicted wrath is the price the card pays for being a five-mana, four-power flyer that protects and threatens at instant speed. It is the rare transforming creature whose back face is partly a punishment, and learning to control when (and whether) the flip happens is the entire skill of piloting her.
