Last updated 2025-12-27

The Arcane Labyrinth (v5.0)

The Arcane Labyrinth is a single-player "Dungeon Crawl" format. The format is designed to allow complex and interesting Magic: The Gathering gameplay and deck building without the need for other players. You control a Hero and their Vanguard to survive 100 rooms of a escalating nightmare.

Thematically, this format can be thought of as a party of adventurers, led by a hero (hero deck), traveling to a dungeon (labyrinth deck). Once there, they setup camp on the outside and prepare to descend (preparation phase). Once inside, they move through the dungeon one room at a time, encountering creatures, traps, mini-bosses, and finally, the dungeon guardian.

This format is constantly evolving and being worked on as I play it. Please reach out at arcane-labyrinth@pm.me, I’d really love to hear about your experience playing the game.

I. Setup & Deck Construction

Your Hero

Choose one Legendary Creature or Planeswalker. It starts on the battlefield. It does not cost mana.

  • Hero Health: You have 20 Life. If this hits 0, the run is a Game Over.

  • The Blocking Rule: If your Hero blocks an attacker and its Toughness > Attacker’s Power, you take 0 damage to your Hero Health. If the attackers power is greater than your heros toughness, it is not Trample mechanics, the full value of their power hits your HP.

  • Your hero is still susceptible to interactions like being exiled/etc. In cases like these, “direct attacks” behave the same as usual magic – they impact your hero’s HP.

    • Restated: you cannot for example exile your hero and then never take any damage. Additionally, any cards or effects that target typical mage life translate to targeting hero HP.

The Hero Deck

A typical 60-card deck. There are virtually no restrictions on what cards can be contained in a 60 card hero deck (except for the noted restrictions below). The hero deck is played basically as normal Magic, and so standard deck archetypes and building advice usually apply

Hero Deck Restrictions:

  • Maximum 1 Artifact card in the main deck (to encourage Shop utility).

The Labyrinth Deck

A 100-card deck (15 Lands, 55-65 Creatures, 20-30 Spells).

  • Must contain no more or fewer than 5 Legendary creatures. If the deck builder does not have legendary creatures, ‘Rare’ creatures may be used. These creatures are meant to represent bosses, so make sure they are powerful and synergize well with the Labyrinth deck!

  • “Classic” or “typical” deck construction rules apply eg limit 4 of a single card type

  • The Labyrinth deck must have at least 1 mana card for each color utilized by the lab. Eg if you have a number of red green cards, must have at least 1 red land and 1 green land

The Secret Shop Deck

A 10–15 (or greater) card deck of Artifacts brought by the player. Conceptually this deck should be thought of as part of the players deck, and should synergize with player cards.

II. The Preparation Phase

The player receives 3 Safe Turns to build their board. They may play lands and cast spells, but cannot directly attack during these turns. Spells that cause damage are allowed and the labyrinth can take damage (card mill) during these phases, but the player cannot directly attack as part of an attack phase.

Restated, these are special turns with no attack phase. Thematically, this can be thought of as the hero/vanguard sharpening their weapons and checking their armor before entering the dungeon.

III. The Dungeon Phase (2-Card Draw)

After the players 3rd turn, they enter the Labyrinth. Every Labyrinth turn, reveal the top 2 cards of the Labyrinth and resolve them in order according to the below rules. The Labyrinth plays at least 2 cards every turn, unless a player card is preventing card draws.

  • Lands: Add the land to your land zone immediately (untapped). It can be used immediately. Lands trigger the Shop Phase after the Dungeon's end phase.

    • Lands are added to your zone in the order they appear. Order matters here. If the land is the first card drawn by the Labyrinth that turn, and the next card is a sorcery that you have a cancel for, that the land now allows you to afford, you can cast the cancel. However the inverse, where the sorcery comes first, would not allow this kind of resolution.

  • Creatures: Enter with Haste and always attack. They follow Vanguard Priority (below) and never block.

  • Spells/Traps: Resolve immediately. The Labyrinth always ignores "additional costs." Resolve spells before creatures enter the battlefield.

  • Enchantments/Artifacts: Applied "globally" to all future rooms until dispelled by the player.

  • Sequential Draws: If the Lab draws cards via an effect, they are played immediately and sequentially.

  • Interpretive Resolution: If an effect is ambiguous, resolve it in the most effective way for the Labyrinth.

IV. The Vanguard System (Combat Priority)

Labyrinth creatures attack your Vanguard in this order:

  1. The Wall: Must attack creatures with Defender, Reach, or Vigilance first.

  2. The Front Line: Attacks your untapped creatures (highest power first).

  3. The Hero: Deals damage to your Hero Health (20) only if no untapped creatures remain.

Note: The player can of course choose to not block with any of these creatures and allow direct damage to their hero’s HP.

V. The Secret Shop & Economy

When a Land is revealed from the Lab, the Shop opens at the end of the turn:

  1. Reveal: Draw 3 Artifacts from your Shop Deck.

  2. Buy: Spend lands equal to the Mana Value of the artifact you want to buy. Spending a land in this context sends it to the player's graveyard. If the artifact has a colored mana cost, you must pay with that mana color. The card goes to your Hand (you must still pay its mana and equip costs).

  3. Scrap: If you don't buy, the card goes to the bottom of the Shop Deck.

VI. Random Encounters (D20 every 3rd Turn)

  • 1-6: System Failure: Sacrifice your strongest non-land permanent. (If only the Hero is active, discard a land).

  • 7–15: Static: No effect.

    16–19: Signal Boost: Draw a card and gain 3 life.

  • 20: Masterwork: Top card of the Shop Deck enters hand for free, draw a card from your library, and gain 3 life.

VII. The Final Boss

The Boss is always at the bottom of the 100-card deck.

  • Boss Equipment:

    • The Boss enters with the most expensive artifact remaining in the Shop deck equipped for free.

  • Speed Scaling:

    • Boss appears in <10 turns: +10/+10.

    • Boss appears in <15 turns: +5/+5.

Additional Rules and Card Resolution Notes:

  • If the Labyrinth encounters “gain X life” interactions, this is resolved by moving X cards from the Labyrinth graveyard back into the Labyrinth deck, in the order they went into the graveyard

Ongoing Balance ideas

"Entropy" Draw (Dynamic Scaling)

Instead of a flat 2-card draw, scale the Labyrinth’s output based on your success.

  • Proposed Rule: If the Player has 10 or more creatures, or any creature with Power 10 or greater, the Labyrinth draws 3 cards per turn instead of 2.

  • The "Desperation" Clause: If the Labyrinth deck is below 50 cards, all Labyrinth creatures gain Trample. This prevents you from "chump blocking" with tiny tokens to save your Hero Health.

Adaptive Difficulty: The "Threat Level"

Introduce a D20 roll at the start of every Dungeon Phase (not just every 3rd turn) once you pass turn 10.

  • Threat Level 1-10: Normal draw.

  • Threat Level 11-19: The Lab draws an extra card.

  • Threat Level 20: The Horde Awakens. All creatures in the Lab's graveyard with Power 2 or less return to the battlefield with Haste for one turn, then are exiled.

The "Vanguard Exhaustion" Rule

To prevent a single "Wall" from stalling the game forever:

  • If a creature with Defender or Vigilance blocks for 3 consecutive turns, it becomes Exhausted. It loses its keywords and cannot block for one turn. This forces you to rotate your defenders and prevents a static board state.