The objective of Boss Monster is to build a Dungeon that will lure in Heroes that can be killed for their Souls to be collected. A player wins when they have collected 10 Souls; players may lose the game if theyget 5 Wounds. In the event that two or more players get 10 Souls or the last remaining players get 5 Wounds in the same turn, then you take the total number of souls and subtract the number of wounds and the largest amount wins. If it is still a draw, the Boss with the lowest XP wins. If a player has 5 Wounds or more at the end of turn phase they lose regardless of soul count.
The number of Hero cards that should be used is based on how many players there are. The player icon located at the bottom part of the Hero cards indicate the minimum number of players that should be playing to use the card. For example, a Hero card with 3 player marks at the bottom should be used when playing with 2 or 3 players. However, one could simply randomly select the suggested number of cards for each amount of players.
2 Players: 13 Ordinary Heroes, 8 Epic Heroes
3 Players: 17 Ordinary Heroes, 12 Epic Heroes
4 Players: 25 Ordinary Heroes, 16 Epic Heroes
*5-6 Players: 37 Ordinary Heroes (25 from BM1 or BM2 and 7 from Crash Landing), 21 Epic Heroes (16 from BM1 or BM2 and 5 from Crash Landing)
This system of randomly selecting becomes necessary when playing with any Promo Cards or Expansions to prevent there from being too many Ordinary Heroes slowing down the game.
The game starts with each player randomly picking as Boss card. Once everyone has a Boss, each player places their Boss at the right end of where their Dungeon will be. The Boss deck is no longer needed after this.
Each player draws 5 Room cards and 2 Spell cards; then, discards 2 cards they don't want. It does not matter if the cards are both room cards, both spell cards, or one of each. After everyone has discarded each gets to place one Room to the left of the Boss cards to start their Dungeon. The Room cards are placed face down and flipped over all at once after everyone has put a Room card down. If any Rooms have a Build Effect that effect happens, otherwise the pre-game ends.
Note: In the event that two or more players' Room's, Spell's, Level Up's, or Item's effects are both played in the same phase and order matters; the Boss with the highest XPs effect takes place first. If there is currently an active player their effects take priority over other players regardless of XP.
Beginning of TurnEdit
One Hero card from the Hero deck is flipped over for each player (so if there are 3 players 3 Heroes are flipped over) and put into "Town"; if the Hero deck runs out of Heroes the Epic Hero deck is used. Next, each player draws a Room card from the Room Deck.
Note: During this phase no cards can be played and no effects can take place.
Note: The order that Heroes are flip over into Town does matter as they will enter Dungeons in the Adventure Phase as they entered Town in the Beginning of Turn.
Each player may build one Room in their Dungeon either to the left of their left most Room or on top of an existing Room. A Dungeon cannot have more than 5 Rooms in a row though (not including the Boss card) so if a player has 5 Rooms and wants to build a Room it must be on top of an existing Room.
Normal Monster and Trap Rooms can be built on top of any other Room card. Advanced Room cards can only be built on top of (not to the left of the left-most Room) a Normal Room card sharing a Treasure Type.
The Room to be built by the player is first placed face-down in the location the player wants the room built at. The player with the highest Boss XP value starts first, followed by the next highest XP and so on. During which, the player who is placing the room face-down is considered the active player such that any spells played by the active player would always resolve first. After all players have taken their chance to place one room card face down, players would then flip open the card they had placed simultanously. These room cards are then considered to be 'built' after they have been flipped over. Once the Rooms are flipped over any "when you build this room," effects/ability would take place and resolved in an order based on XP value of the player's Boss monster.
Additionally, if a Dungeon reaches the maximum 5 Rooms as the Room is flipped over the Boss's Level Up ability takes effect before the phase ends. Level Up abilities must be used as the Dungeon Reaches 5 Rooms. The abilities cannot be saved for later and only happen the first time the Dungeon reaches 5 Rooms. If a player decides not to use, or forgets to use their Level Up ability when it activates they lose it for good.
Note - Spells playable in the Build phase cannot be played after the rooms are revealed. Effects also cannot be played with the exception of 'build this room' and 'level up' effects.
All players compare how much of each of the four Treasure Types they have. The Heroes in Town will go to to the left of the left-most Room of the Player with the most of the same Treasure as the Hero. If there are any ties for Treasure any Heroes with those Treasure Types stay in Town.
Like in the Build Phase, players take turns being the active player based on XP; the boss with the highest XP goes first and the boss with the lowest goes last. Each Hero goes through the Dungeons in the order that they showed up to Town one at a time. Heroes start in the left-most Room and work their way right taking the respective damage from their HP for each Room. It is imporant the Heroes go through each Room in order as some Room have special effects that may send the Hero back or cause an effect if a Hero dies in a specific Room.
If a Hero is going through a Bosses Dungeon that Boss becomes the Active Player. This means that any Spells, Room Effects, or Items that the Active Player uses always come before any done by other players if order is important.
If a Hero is killed in a Dungeon before reaching the Boss Chamber that Hero becomes a Soul and is placed face-down next to the Wound pile (so two cards lengths right of the Boss card). However, if a Hero enters the Boss Chamber it counts as a Wound against the boss and is place face-up just right of the Boss card.
note: Spell cards marked with an axe can be played during this phase.
End of Turn PhaseEdit
All deactivated Room become reactivated, any effects that end when the turn is over end now. If a Hero was sent back to Town or for some reason went part-way through a Dungeon without completing all of their HP is restored at this point.
At this point, if any players have 10 Souls go to the End of Game Phase. If any players have 5 Wounds leaving 1 or 0 players without 5 Wounds also go to the End of Game Phase. Otherwise, go back to the Beginning of Turn Phase. If a player has 5 Wounds but there are at least 2 players left, the game continues to the Beginning of Turn Phase however, the players with 5 Wounds are out of the game.
End of Game PhaseEdit
If only one player has 10 Souls or only one player is left without 5 Wounds that player is declared the winner and the game is over. If multiple players get 10 Souls in the same turn or all players left have 5 Wounds the victory goes to the Boss with the lowest XP.
The lowest XP rule does not include players who did not earn 10 Souls or that died in a turn before the last End of Turn Phase.
When a Boss reaches the 5 Room limit and Levels Up a player may place some sort of token(ie. coins, markers, etc) over the upper left-hand corner of the Boss card to indicate the Boss has leveled up because a Boss's Level Up can only be used once per game. This allows other to easily keep track of which player has used their ability.
The Kickstarter of Boss Monster includes golden Token coins for this purpose. Replacing the boss with a foil version boss cards could also be used for the same purpose. However, not all copies of the Base Set include these so they are not official rules.
The mini-expansion Tools of Hero Kind releases a Card Type, Item Cards. Only one Item card is active at any time. Once a Hero with an appropriate Treasure Type comes into Town that Hero takes the item, This Item grants the Hero some kind of "Power-Up when it is in a Dungeon, such as the ability to skip over any Monster Room.
If a Hero with an Item is defeated and turned into a Soul that Boss gets the Item card. This card's "Reward" may be used by the Player just like Spell cards are used.