School abjuration; Level 3
Casting Time 1 hour (2 phases of 30 minutes; automatically fails if interrupted)
Components V, S
Optional Components F (a rendering of the Elder Sign gives a +2 insight bonus on all ritual skill checks), F (the Celeano Fragments or another source of all three renderings give a +5 insight bonus on all ritual skill checks and increases casting time to 3 hours in 2 phases of 90 minutes)
Skill Checks Knowledge (arcana) or Profession (Yog-Sothothery philosopher) DC 15, 1 success (diagram); Knowledge (planes) or Profession (Yog-Sothothery philosopher) DC 15, 1 success
Diagram Elder Sign of any size on object touched; for every 5 feet of its radius, increase the diagram skill check DC by 1
Target object touched
Saving Throw none; Spell Resistance no
Backlash The drawer of the Elder Sign gains one temporary negative level (Fortitude save DC 15 to remove) This ceremony creates an Elder Sign on the touched object. An Elder Sign is immune to the attacks, spells, and abilities of a Great Old One, Outer God, or creatures bound to their service (including species like deep ones or tcho-tcho), and they may not touch or pass through an object with the Elder Sign. Generally, an Elder Sign is destroyed after being within 30 feet of a Great Old One or Outer God for more than 5 continuous rounds. Note that since only the Elder Sign itself has immunity to various alien horrors, its protection may be unreliable. For example, a shield with the Elder Sign drawn on it would not be affected by a Great Old One’s attack, but the monster could still strike the bearer if it avoids striking the shield.
Engraving the sign upon a door or on an archway will prevent such creatures from passing through the portal.
Sandy Petersen’s Cthulhu Mythos, © 2017, Petersen Games; Authors: Sandy Petersen, Arthur Petersen, Ian Starcher.