Invert Existence (Blue)

You may play this from your banished zone.

Banish up to 2 cards in an opponent's graveyard. If an attack action card and a non-attack action card are banished this way, deal 2 arcane damage to them.

Blood Debt

Rulings

From the Monarch release notes

You cannot defend with Invert Existence as it does not have a defense value.
You may banish any cards from an opposing hero’s graveyard, not just action cards.
You cannot banish 1 card from two different graveyards. They must all be from one opposing hero’s graveyard
You do not choose targets. You pick the cards when Invert Existence resolves. There is no window for priority after the cards are picked but before they are banished. I.e if you want to play a card that prevents arcane damage or gains you life, do it in response to this card. Prevention and replacement effects such as spellvoid/arcane barrier do not need to be activated in response.

Keyword notes

Blood Debt - Blood Debt is a new keyword existing on Shadow cards. Shadow cards can inflict a loss of life to access a greater power. At the end of your turn, you lose 1{h} for each blood debt card in your banished zone.

You only lose life at the end phase. Players do not have priority during the end phase.
If you have multiple cards with blood debt, you lose 1 for each instance of blood debt at the end of turn.
Only face-up cards banished with blood debt counts and will lose you . Face-down banished cards have no effects or stats.