For those attempting to run Tatters of the King using World of Darkness rules like I did, or who would simply like to add Hastur or a Hastur-like figure into their World of Darkness mythology, you can find the 'Free Hastur' spell below. It has been designed using similar rules to what you will find in the Second Sight book. If you would like to read other articles like this one, you can take a look over here.
Effect: This chant draws the Hastur to Earth and binds it into an area bounded by the nine stone monoliths used for Call Hastur. Once freed, Hastur imbues the soil within those nine stones and is treated as a powerful Earthbound from Demon: the Fallen. Multiple participants may be involved and each one can make a sacrifice to gain a roll and add their successes to the total pool. Approximately 35 participants are required to complete the ritual if performed in Carcosa after summoning each Spawn of Hastur.
Dice Pool: Presence + Occult.
Minimum Successes Required: 350 (Hastur) or 180 (Spawn of Hastur).
Ritual Length: 10 minutes per roll.
Duration: A year and a day unless recast.
Cost: 1 permanent Faith OR Willpower dot per roll. If you aren't using the Demon: the Fallen cosmology, only Willpower may be sacrificed.
Suggested Equipment: Each Spawn of Hastur present within the ritual area provides 50 successes to each subsequent casting of Free Hastur. Casting this spell within a space where the barriers between the Arcadian Realm of Carcosa and Earth are weakened provides an additional 100 successes to the casting of this spell.
Suggested Penalties: Attempting to cast this twice in one night levies a -5 penalty to each roll.
Ritual Details: This chant draws the Hastur to Earth and binds it into an area bounded by the nine stone monoliths used for Call Hastur. This spell can only be cast at night with Aldebaran visible. Unless cast in Carcosa with four Spawn of Hastur present, Hastur's arrival will last for only one hour. If this spell is disrupted, Hastur will nonetheless appear for only a single minute before being torn back to the Abyss.
Drawback: Hastur may be present but he is under no compulsion to avoid injuring, slaying, or devouring the summoners.