School necromancy; Level 5
Casting Time 2 hours. If ritual is interrupted before the 2 hours are up the ritual fails completely.
Components M (1 gallon of blood from the target), SC (at least 5 and up to 10, chanting from text; +1 bonus on non-diagram ritual skill checks per optional caster)
Skill Checks Knowledge (arcana) or Profession (Yog-Sothothery philosopher) DC 15, 1 success (diagram); DC 20, 1 success
Diagram target must be bound in the center of a 10-foot-diameter circle (any material works for all parts of the circle except the glyphs, which must be drawn in the sacrificial victim’s blood)
Target helpless humanoid or monstrous humanoid touched
Saving Throw none; Spell Resistance no
This ritual replenishes magical power by sacrificing a humanoid or monstrous humanoid as fuel. The target must be killed at the end of the ritual by the primary caster, typically using a spell or enchanted weapon.
When this happens, the primary caster gains a number of spell slots equal to the victim’s Hit Dice. Spells of 2nd level cost 2 Hit Dice, spells of 3rd level cost 3 Hit Dice, and so forth. These spell slots can be used to cast or prepare spells as the primary caster normally can and may exceed the primary caster’s usual maximum, but fade after 24 hours.
Sandy Petersen’s Cthulhu Mythos, © 2017, Petersen Games; Authors: Sandy Petersen, Arthur Petersen, Ian Starcher.