Setup

Before playing each game, perform the following steps in order. If you want to play a solo game with a single investigator, don't put any component with the Teamwork trait in the game.
Some game components and effects are handled "before setup", notably Prelude.

## Main Setup

1. **Place Game Board**
Unfold the main board and place it in the center of the play area within easy reach of all players.
2. **Organize tokens**
Organize the following tokens as listed below:
	1. Create the Gate stack by randomizing the main board Gate tokens, and placing them facedown (common side up) in a stack within reach of all players.
	2. Create the  Clue pool by placing the Clue tokens facedown (common side up) in a pile within reach of all players and randomize them.
	3. Create the general token pool by taking all  Health,  Sanity, Improvement, Impairment,   Focus,  Resource, Travel Tickets, Eldritch,  Mystery, and  Rumor tokens and place them in piles within reach of all players.
3. **Choose and Place Investigators**
Players agree upon one player to receive the Lead Investigator token. If they cannot decide, players assign this token to a random player as they see fit (for example, by rolling a die). Starting with the Lead Investigator and proceeding clockwise, each player chooses one investigator. He takes the corresponding Investigator sheet, then places the matching Investigator token on the game board space listed on the back of his Investigator sheet.
4. **Receive Starting Possessions, Health, and Sanity**
Each investigator receives the starting possessions listed on the back of his Investigator sheet. He gains any tokens, Conditions, Assets or Spells listed by taking the matching card from the game box, their respective decks, discard piles, or reserve. If the starting possessions are not in these places, such as if another investigator or a defeated investigator has them, the new investigator does not start with those possessions. Then he takes a number of Health and Sanity tokens equal to his investigator’s maximum Health and Sanity listed on the front of his Investigator sheet. He places these tokens near his Investigator sheet.
5. **Determine Ancient One**
As a group, players choose one of the Ancient One sheets. Each Ancient One provides a different game experience. For their first game, it is recommended players choose Azathoth, as he is the most straightforward Ancient One. Place the chosen sheet faceup (displaying a  Doom value in the top left corner) near the game board and resolve any setup effects on the sheet.
6. **Create Monster Cup**
Take all non-epic Monster tokens and place them in an opaque container such as a bowl, mug, or the cover of the game box. Then shake this container to randomize the Monster tokens. Do not place the Epic Monster tokens in the Monster cup. Epic Monster tokens are marked by their red color and clipped lower-left corner.
7. **Separate and Place Decks**
Take all Location Encounter cards, Research Encounter cards, Special Encounter cards, Mystery cards, Adventure cards, and Mystic Ruins Encounter cards that do not correspond to the chosen Ancient One or Prelude and return them to the game box. Those cards will not be used for this game. Cards correspond to the chosen Ancient One can be identified by an illustration of its corresponding Ancient One on the card’s back.

Then separate all other cards as listed below and place them near the game board.
— Shuffle all Expedition Encounter cards and Mystic Ruins Encounter cards facedown each into a single deck, regardless of card back. Then one player cuts the decks.
— Set the Mythos cards aside for step 8.
— Separate all double-sided cards into decks by types (Spells, Conditions and Unique Assets). Place these decks faceup, with the top card's name and artwork visible. Then one player cuts the deck.
— Separate all one-sided cards into decks by card back and shuffle each deck facedown.
8. **Build Mythos Deck**
This deck is built differently each game, based on the instructions at the bottom of the Ancient One sheet. To build this deck, perform the following steps:
	1. Separate all Mythos cards into three piles, based upon the color on the front of the card (green, yellow, and blue). Shuffle each separately, and place them facedown.
	2. Build stage I of the Mythos deck by taking random cards of the denoted colors and quantities (listed at the bottom of the Ancient One sheet) and shuffling them together. Do not look at the cards at this time.
	3. Then build stage II of the Mythos deck (following the same steps as stage I) and place it under the stage I deck.
	4. Finally, build stage III of the Mythos deck and place it under the stage II deck to create a single Mythos deck. Once created, do not shuffle this deck. Place the deck near the Ancient One sheet. Return all remaining Mythos cards to the game box without looking at them.
9. **Resolve Starting Effects**
Before resolving this step, if the chosen Prelude or Ancient One requires the use of any side board, resolving the Side Board Setup section first. Resolve the following effects to complete setup:
	1. Place the Reference card that corresponds to the number of players near the Mythos deck. Players use the Reference card when resolving Mythos effects. Return all other Reference cards to the game box.
	2. Place the Doom token on the space of the Doom track listed on the upper-left corner of the Ancient One sheet. For example, the Azathoth sheet denotes that the Doom token starts on the "15" space of the Doom track.
	3. Place the Omen token on the green (comet) space of the Omen track.
	4. Place the top four cards of the Asset deck faceup in the four slots of the reserve (at the bottom-left of the game board).
	5. Spawn the number of Gates indicated on the Reference card. To spawn a Gate, take the top Gate token from the Gate stack and place it faceup on the space indicated on the Gate token. Then draw one random Monster token from the Monster cup and place it on the same space.
	6. Place the Active Expedition token on the space that corresponds to the illustration on the back of the top card of the Expedition Encounter deck.
	7. Spawn the number of Clues indicated on the Reference card. To spawn a Clue, take one random Clue token from the Clue pool and place it facedown on the space indicated on the face of the Clue token.
	8. Finally, draw one Mystery card and place it near the Ancient One sheet. Then resolve any "When this card enters play" effects on that card.

## Side Board Setup

If a Prelude or Ancient One requires the use of any side board, place it near the main board within reach of all players. While the side board is in play, "game board" refers to both the main board included in Eldritch Horror and the side board. "Side board" refers to the side board but not the main board. Follow the steps below to setup the side board.

1. **Place Side Board**
Unfold the side board and place it near the main board within reach of all players.
2. **Add Clues And Gates**
Add the  Clues and Gates that correspond to spaces on the side board to the Clue pool and Gate stack, respectively, and randomize the Clue pool and Gate stack.
3. **Set Aside Monsters**
Set aside any Monsters required by the side board from the Monster cup:
— Antarctica side board: 1 Elder Thing Monster, 1 Giant Penguin Monster, 1 Proto-Shoggoth Monster, and 1 Shoggoth Monster.
— Egypt side board: 1 Mummy Monster, 1 Sand Dweller Monster, and 1 Spawn of Sebak Monster.
— Dreamlands side board: 1 Ghoul Monster, 1 Moon-beast Monster, 1 Nightgaunt Monster, and 1 Zoog Monster.

If any of these components would be returned to the Monster cup, it is set aside instead.
4. **Separate And Place Decks**
Separate all cards required by the side board into decks and shuffle each deck:
— Antarctica side board: Outpost Encounters, Mountain Encounters, and Antarctica Research Encounters.
— Egypt side board: Egypt Encounters and Africa Encounters.
— Dreamlands side board: Dreamlands Encounters and Dream-Quest Encounters.

Place these decks near the side board.
If the Dream-Quest Encounter deck is used, place the Dream-Quest Token on the space that corresponds to the top card of the Dream-Quest Encounter deck.
5. **Spawn Dream Portals**
If the Dreamlands side board is used, put the three Dream Portals in the order of your choice. Then for one Portal at a time, reveal Gates from the top of the Gate stack until you get a Gate that corresponds to a space not on the Dreamlands side board and does not already contain a Dream Portal, then place the Dream Portal token on that space. Leave each revealed Gate in the Gate stack and do not randomize the Gate stack after spawning a Dream Portal.

## Optional Rules

Some groups may find Eldritch Horror too easy or too challenging. If all players agree at the start of the game, they can make the game easier or harder as listed below.

### Mythos Deck

Players can alter the game's difficulty when building the Mythos deck on step 8.

* **Easy Game Difficulty**
Players can make the game easier by returning all hard Mythos cards (with red tentacles) to the game box before building the Mythos deck.
* **Hard Game Difficulty**
Players can make the game harder by returning all easy Mythos cards (with a blue sigil) to the game box before building the Mythos deck.
* **Insane Game Difficulty**
Players can make the game *significantly* harder by building the Mythos deck using only hard Mythos cards. This optional rule may require additional expansions depending on the chosen Ancient One.
* **Staged Difficulty**
Players can make the game's difficulty increase in stages by building stage I of the Mythos deck using only easy Mythos cards, building stage II of the Mythos deck using only normal Mythos cards, and building stage III of the Mythos deck using only hard Mythos cards. This generally makes the game easier since investigators will have more time and resources to prepare their characters.
To increase the difficulty of this optional rule, players can use normal blue Mythos cards when building stage I of the Mythos deck and hard blue Mythos cards when building stage II of the Mythos deck. Players may also start with an easy blue Mythos card in play following the "Starting Rumor" rule below.

### Starting Rumor

If players want a greater challenge, they may choose to begin the game with one starting Rumor Mythos card. After setup, draw one unused Rumor Mythos card from the game box and place it in play. Resolve any "When this card enters play," effects, as well as the Space token icon (if it appears on the card). Do not spawn  Clues from the Rumor's  icon.

### Control Your Fate

Instead of drawing a random Prelude card before setup, players as a group may choose one Prelude card, following the card’s effects as normal. Alternatively, players may choose to not use a Prelude card.

## References

1. ↑ Official answer from Nikki Valens for spawning Dream Portals on  *BoardGameGeek*.