Thieving AvenHow it works & interactions with other cards

Understanding Heist and Growth

Thieving Aven has two distinct triggered abilities. The first triggers when it deals combat damage to a player, allowing you to heist their library. The second is a triggered ability that monitors when you cast a spell you don't own. When you heist a library, you look at the top three cards of that player's library, exile one face down, and put the rest on the bottom in a random order. You may cast that exiled card for as long as it remains exiled, using mana of any color to do so. Each time you cast such a spell, Thieving Aven receives a +1/+1 counter.

Resolution Step-by-Step

First, Thieving Aven must deal combat damage to a player. Once damage is dealt, the heist ability goes on the stack. When the ability resolves, you choose an opponent (usually the one damaged) and look at the top three cards of their library. You select one to exile face down and return the others to the bottom. Later, when you decide to cast that exiled card, the Aven's second ability triggers. This growth trigger goes on the stack on top of the stolen spell, meaning Thieving Aven will get its +1/+1 counter before the stolen spell actually resolves.

Common Pitfalls

A common mistake is forgetting that you must still pay the mana cost for the heisted card; heisting does not make the spell free. Additionally, the heist ability only triggers on combat damage, not any damage dealt by the creature. If Thieving Aven leaves the battlefield, you can still cast any cards you previously heisted with it, but the Aven will no longer be there to receive +1/+1 counters from those spells.

When to Play Thieving Aven

Thieving Aven is best played early in the game when opponents lack flying blockers. This ensures you can start heisting cards as soon as possible. It is particularly effective against decks that run high-impact utility cards or powerful creatures that you can use to bolster your own board state while growing your Aven into a lethal threat.

Interaction examples

Double the Heist

Roaming Throne

If you have Roaming Throne on the battlefield with 'Bird' or 'Rogue' chosen as the creature type, Thieving Aven's combat damage trigger will fire twice. You will heist the opponent's library two separate times, exiling two different cards. Furthermore, when you cast those stolen spells, the Roaming Throne will cause the +1/+1 counter trigger to fire twice for each spell, doubling the growth of your Aven.

Stealing Utility

Solemn Simulacrum

Suppose you heist your opponent's Solemn Simulacrum. When you cast it, Thieving Aven's second ability triggers, giving it a +1/+1 counter. As the Solemn Simulacrum enters the battlefield under your control, you search your library for a basic land. If the Golem later dies, you (the controller) draw the card, even though your opponent owns the card.