Whenever you gain life, target opponent loses that much life. When Enduring Tenacity dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Impending 5—{1}{B} (If you cast this spell for its impending cost, it enters with five time counters and isn't a creature until the last is removed. At the beginning of your end step, remove a time counter from it.) Whenever this permanent enters or attacks, mill four cards, then you may return a non-Avatar creature card or a planeswalker card from your graveyard to your hand.

If this card is in your opening hand, you may begin the game with it on the battlefield. If you would gain life, you gain that much life plus 1 instead. As long as you have at least 7 life more than your starting life total, creatures you control get +2/+2.

Flash When this enchantment enters, target creature an opponent controls gets -3/-3 until end of turn. Creatures your opponents control can be the targets of spells and abilities as though they didn't have hexproof. Ward abilities of those creatures don't trigger.