Starting Info

Create your deck of 24 cards before your battle begins. Starter decks come pre-made, but you can change them in any way.

To create a deck, you need the following cards, all of the same color:

  • 1 boss

  • 3 different wizards

  • 10 summons (kept in your "castle")

  • 10 spells (kept in your "spellbook")

  • Up to 8 reserve (backup) cards, which can only be summons or spells

You can only have up to 4 copies of the same summon or spell in your deck.

Not your first trading card game? Read here!

The most common trading card games keep all of their cards in one pile, called the deck. However, in this game, the deck is split into multiple piles. You have your "castle" for your summons and your "spellbook" for your spells. You will have complete access to any card in your castle or spellbook at any time, and they should be treated as hidden information in the same way a normal deck would be.


Also, it helps to remove any preconceptions you have about trading card games before you start playing. Many mechanics in this game are similar to other ones, but since this is a different game, there will be differences. It is better to learn with a fresh mind!

Setting Up

To set up a game of BOS, you will need to first set up your battlefield. The battlefield is the area where all the cards you are actively using are kept. You and your opponent will need to align your battlefield in a specific way.

  • Form three columns with your opponent, with one wizard on each end, leaving about two cards' length in between them. These columns are represented with the wand icons for the wizards, and the summoning circles with hands coming out of them for where your summons will go. These columns play a big role in strategy, so make sure they are properly aligned!

  • Next, place your boss to the left of where your summons will go. It is represented with the demon icons below.

This is what your battlefield should look like after it is completely setup:

You will also need to set up spots to keep all of the cards you are not actively using. Gather all of your summons and place them in a pile called your "castle." This pile should be placed face-down in a spot that is comfortable for you to reach, but still plainly in view of your opponent(s). Do the same for your spells and place them in your "spellbook." You will need one extra space for your used cards (called your "graveyard"), so leave room for that as well. The graveyard is kept face-up, but your castle and spellbook should be face-down because only you know what is in them.

(Additionally, if you are using a reserves pile, you must keep that within view of your opponent(s) at all times as well. It should be placed further away from the main play area to avoid interacting with it on accident while in the middle of a game)

Life and Vim

Each player begins the game with 30 life. Bring your opponent's life down to 0 to win!

Each player also begins the game with 1 vim, which can be spent to cast spells. At the start of a player's turn, their vim doubles. Your vim will continuously grow, going from 1 to 2, then 4, then 8, and so on. Make sure you don't run out of vim! If you try to double 0, you'll still have 0 left.

It is recommended to have the BOS app (in development for android and ios) and some dice to keep track of these numbers, however you may also play using a normal calculator for each player to keep track of vim.

Starting a match of BOS

  1. Greet your opponent and reveal the color of your deck.

  2. Determine who goes first by playing rock-paper-scissors, letting the winner decide. (Do not use anything luck-based to determine who goes first!)

  3. You may swap cards from your reserves into your deck, keeping 10 summons in your castle and 10 spells in your spellbook. (Remember to keep your cards a secret)

  4. Set up your battlefield, with your boss and wizards face-down.

  5. Play the game!

  6. Loser of the most recent game determines who goes first. They may also change the positions of their wizards. (Winner cannot) (Decide where your wizards will be in secret so the opponent is at a disadvantage)

  7. Repeat steps 3-6 until the victor is decided!