First Appearance: Sentinels of the Multiverse: Infernal Relics
Who he is: The fallen angel of the Multiverse
Initial Side: Infernal Emissary
Innate Power (Initial Side): At the end of the villain turn, Apostate deals the hero target with the highest HP (H)—where H is equal to the number of heroes—minus 2 melee damage and (H) minus 2 infernal damage.
Advanced Power (Initial Side): At the start of the game, look through the villain deck for the Tome of the Unknowable and put it into play. Shuffle the villain deck.
Villain Cards that Begin Game in Play: Condemnation (11 HP): At the end of the villain turn, Apostate deals the hero target with the highest HP 3 melee damage. Reduce damage dealt to this card by 1.
How he flips to his other side: When he would be reduced to 0 or fewer HP and there is a villain relic in play, destroy the villain relic with the lowest HP and he flips.
Nemesis: Fanatic

Second Side: Dark Corruptor
Innate Power (Second Side): When flipped to this side, restore Apostate to 20 HP. At the end of the villain turn, Apostate deals the hero target with the lowest HP (H) minus 2 melee damage, then regains (H) plus 2 HP.
Advanced Power (Second Side): Whenever a demon card is destroyed, play the top card of the villain deck.

Most Fiendish Ongoing Card: Apocalypse: At the start of the environment turn, destroy all cards in play other than this card, character cards, and relics. Then, destroy this card.
Most Fiendish One-Shot Card: Profane Summons: Reveal cards from the top of the villain deck until (H) minus 1 relics are revealed. Put them into play. Shuffle the other revealed cards back into the villain deck.
Most Fiendish Villain Target Card: Relic Spirit (9 HP): At the end of the villain turn, each relic regains 1 HP. When this card is destroyed, move (H) minus 1 relic cards from the villain trash into play.

How to Defeat Apostate: You have to plan when you lower Apostate’s HP to zero or lower. He can’t have any relics in play or else he flips. In fact, he flips instead of taking the last few hit points of damage even if he’s on his second side. So, you have to take out relics. But you don’t have to worry too much about Demons.

Still, you don’t want too many Imp Pilferer’s in play because they’ll wreak havoc on your ongoing and equipment cards, and you can’t deal as much damage to Apostate if Fiendish Pugilist is in play. But Relic Spirit gets the nod for most fiendish demon because she has to stay in play—or else more relics come into play—and she heals other relics making it even more difficult to defeat Apostate.

Then there are relics. Many of them have nasty effects, but the worst of these have to be Condemnation, Tome of the Unknowable, and Runes of Malediction. The first one deals the most damage, while the other two have a nasty habit of putting more villain cards on the table. Knock these out first, and then take on the rest of the relics. After that, turn your attention to Apostate.