When the game ends, the player with the highest Doom (and all 6 of his or her Spellbooks) will be named the winner. The Doom Phase is the most common time for players’ Doom to advance; it is also the Phase in which the end of the game is most likely to be triggered. The Doom Phase has two steps, to be completed in order:
Advance each player’s Doom Marker a number of spaces along the Doom Track equal to the number of Gates they Control. For example, a player Controlling 2 Gates will advance 2 spaces along the track. Players can do this simultaneously. Abandoned Gates do not provide Doom.
Starting with the First Player and proceeding in player order, each player has the option to perform a Ritual of Annihilation. Each player may only perform a single Ritual of Annihilation at this time.
Rich is First Player; he has three Controlled Gates and Nyarlathotep in play. At the start of the Doom Phase he advances his Doom Marker three spaces, for his three Gates. All other players also advance according to their Gate totals. As the First Player, Rich has first choice of whether to perform a Ritual of Annihilation; he chooses to do so. The Ritual Marker is on the “5” space, so Rich pays 5 Power and advances the Ritual Marker to the next space, which shows a 6. Rich now advances his Doom Marker another three spaces (for his three Gates), and receives an Elder Sign for Nyarlathotep, his Great Old One. In this Doom Phase, Rich advanced a total of 6 spaces along the Doom Track and he received an Elder Sign. As Rich’s Ritual moved the marker along, the next player to perform a Ritual of Annihilation must pay 6 Power. If Rich had not performed the Ritual of Annihilation he would have had 5 more Power upon entering the Action Phase, but he would not have gained the Elder Sign and 3 extra Doom.
If the Ritual Marker is on 10 and a Ritual of Annihilation is performed, the Ritual marker moves to the “Instant Death” space. This means that the game will end at the completion of this Doom Phase, and the victor will be determined. See the section titled Victory: Ending and Winning the Game here for more details.
Players who have not yet had a chance to perform a Ritual of Annihilation when the Ritual Marker is advanced to “Instant Death” may still choose to perform a Ritual when it is their turn to choose. The Power cost for all subsequent Rituals is 10. Remember, in the Doom Phase each player gets exactly one chance, in player order, to perform a Ritual. This is true even in the Doom Phase in which “Instant Death” has been reached.
Some Spellbooks, special abilities, or even Spellbook requirements take effect during the Doom Phase. These will usually occur when it is your turn to perform a Ritual of Annihilation (whether you perform the Ritual or not).
Examples include Black Goat’s Blood Sacrifice Spellbook, and Great Cthulhu’s two Doom Phase Spellbook requirements. Some other events (including those from certain expansion products) may also occur at this time.
If you can use multiple abilities or events, you can choose the order in which you perform them. Example: the Tcho-Tcho can Awaken Ubbo Sathla in the Doom Phase by Eliminating a High Priest, and can also be forced to Eliminate all their High Priests for Elder Signs with Tablets of the Gods if they perform a Ritual of Annihilation. They can choose to Awaken Ubbo Sathla first and then perform the Ritual (and Eliminate all remaining High Priests), or perform the Ritual first, Eliminating all their High Priests and thus becoming unable to Awaken Ubbo Sathla!
Once all players have advanced the Doom Track for their Controlled Gates, had a chance to perform a Ritual of Annihilation, and performed any special abilities, play will move on to the Action Phase, thus restarting the cycle of Phases.