Casting Time 24 hours or less (1 phase of 1 hour plus phases of 4 hours and any fraction thereof; any interruption causes automatic failure); see text
Components V, S, M (fresh blood from eight Medium or two Large creatures), F (a wind instrument which is played by at least one caster, a tome such as the Necronomicon containing the ritual), SC (at least 2 and up to 12, each chanting from text; +1 bonus on non-diagram ritual skill checks per 2)
Skill Checks Knowledge (religion) or Profession (Yog-Sothothery philosopher) DC 20, 1 success (diagram); Knowledge (planes) or Profession (Yog-Sothothery philosopher) DC 14, 1 success per 4 hours of ritual or fraction thereof
Range close (25 ft. + 5 ft./2 levels)
Diagram The circle is 30 feet in diameter and may be drawn with any material, except the glyphs which must be drawn in blood and refreshed repeatedly throughout the casting. No participant can stand inside this circle except to refresh the glyphs with blood.
Effect one Servitor of the Outer Gods
Saving Throw Will negates; Spell Resistance yes
This ritual calls a servitor of the Outer Gods at the center of a large ritual circle. The servitor so called will often in turn summon other servitors or eldritch horrors with malign intent to bring forth something beyond the casters’ ability to deal with.
Sometimes, it may be the creature’s goal to parley and offer knowledge to the casters, and at other times its primary desire is to summon a Great Old One or other horrendously destructive entity.
Tomes containing this spell occasionally recommend not casting it under conditions in which it could accidentally summon powerful creatures that can immediately summon other creatures, since the required circle is often sufficiently magically charged and large enough for the servitor to summon nearly any creature it desires after it arrives.
The ritual’s casting time can be shortened to a minimum of 1 hour by sacrificing prepared conjuration spell slots, which reduce the casting time by 1 hour per spell level so used. Spellcasters who cast spells spontaneously can sacrifice available spell slots this way so long as they know a conjuration spell of that level.
Sandy Petersen’s Cthulhu Mythos, © 2017, Petersen Games; Authors: Sandy Petersen, Arthur Petersen, Ian Starcher.