Rules of «Demon Invasion»
This page collects the main rules. The full handbook with demons, investigators, monsters and cards is inside the game itself: the link «Skip to the handbook» is at the top of the game page.
What the game is about
This is a cooperative game: all investigators win or lose together. Your goal is to solve three mysteries of the demon before the Mythos deck runs out. The game follows the rules of the board game Eldritch Horror, while its texts, names and cards are its own. The game is hard: you will lose more often than you win. One to eight people can play, alone or online.
The round
- Action phase: each investigator has two actions, each no more than once a round. These are moving one step (and further with tickets), resting, focusing, buying items, taking a ticket, casting a spell, trading and the investigator’s special action.
- Contact phase: first you fight every monster in your location. If no monsters remain, you choose one contact: clue search, gate, special mystery contact, expedition, rumor or a location event.
- Mythos phase: one card of the Mythos deck is revealed.
Checks and combat
A check is a roll of dice for a skill: Strength, Knowledge, Observation, Will or Influence. A die succeeds on 5 or 6. In combat you first make a Will check against the monster’s horror, then a Strength check: each success wounds the monster and weakens its counterblow.
Clues and mysteries
Clues lie on the board as tokens: to take a clue you need a search contact with a successful check. Mysteries advance only in the contact phase. Most often you must come to where a mystery sign lies, pass a special contact of two checks and spend clues. Other mysteries require closing or sealing gates, defeating monsters or completing expeditions. The number of signs needed is usually half the number of investigators, rounded up.
Mythos deck, omen and Doom
A deck of 15–16 yellow, green and blue cards is built from the demon’s sheet. Yellow card: the omen advances, a reckoning comes and new gates open. Green: the omen advances, monsters surge and clues appear. Blue: clues appear and a rumor starts. When the omen advances, Doom drops by 1 for each open gate of its color. Closed gates do not give Doom back. When the deck runs out, the game is lost.
Elimination and awakening
An investigator whose health or sanity drops to zero is out, and Doom drops by 1; at the end of the Mythos phase a new investigator takes their place. If Doom reaches zero, the demon awakens: there are no more replacements, and besides the three mysteries you must also solve the demon’s final mystery.
Victory and defeat
- Victory: three mysteries are solved, and if the demon has awakened, its final mystery too.
- Defeat: the Mythos deck has run out, or all investigators are out and there is nobody to replace them.
Difficulty, records and saving
There are four difficulty levels: easy, normal, hard and nightmare. They change Doom, the reserve of health and sanity and the make-up of the Mythos deck; a lone investigator gets help. A victory is recorded in the hall of fame under your nickname; since version 4.0 the hall of fame has been started anew because the rules became stricter. A game can be saved and continued within two weeks.