The Castle of the Prism is a flying crystal fortress of six colored towers that captures souls in its gems and confers on its master the title of Horseman of War.
This name refers to different places in 2 worlds; the versions are not merged.
| Type | Place (floating fortress) |
| Worlds | Antiterra · Vala |
| Spanish entry | Castillo del Prisma |
In Antiterra
Solomon advises not to approach it.
Description
Six great crystal towers, each with a gem of its color — red, orange, yellow, green, blue and purple — stand in its courtyard. The whole is built of colored crystal. It floats in the sky, medieval in style, “500 by 500 meters or more”, with a white rim at its center. A cloud covers it through which the light of sun and moon enters: “it works as a prism”. Its sky has a black center, like a hanging veil.
Inside are panoptic colored chambers, a cavern above the throne, and a highest dome that serves as “Sancta Sanctorum”; its halls hold gems and magic objects.
Location
There is only one; no one holds it at the outset, and it is contested. In its flying phase it hovered above Zaira, though it is a separate place from that city; after Zaira’s destruction it appeared “flying over another place”. In the cosmology of the planes it lies “between the fourth and the fifth” level; it is also said to be on the fifth plane.
Function
- Key: “the gems, when the six come together, make the prism, and then they can summon the Central Tower”.
- Soul prison: whoever takes the castle can “grab all the souls” in “a kind of concentration camp” on Mount Analogue; mortal souls are captured and stored, many at a time, in the gems.
- Title: dominion of the castle gives what is needed “to make the Horseman”, the permanence of power and the title of Horseman of War. In the hands of daemons, “in particular the agents of the apocalypse”, it gives “a power that will let them change things in the primary” plane.
Defenses and contacts
The crystal gate closes the perimeter; a dimensional anchor prevents teleporting in; underground exits are rumored, “perhaps known only to the masters”. It “had other contacts with Spelljammer and with people from other planes”. Delegations of mostly four-armed creatures descend from it, awaited below as “our visitors from the Castle of the Prism” for a festival. Legend says “the ship of chaos dragged it once to carry all the demons and attack Mecanus”, and it is suspected of doing so again.
The crystal nexus
Its support and only known weakness is the crystal nexus. When it bursts, “all the crystals of the castle fly”, the castle automatically rises far from the ground and then “begins to fall”.
Not to be confused with
Earthly castles in the records (Castello Sforzesco, Poppi, Imola, the red-stone castles near Florence and Kosovo, castles in Serbia and Cyprus) and stone-fortress descriptions (white limestone, three-meter walls, an obsidian tower) are not the Prism.
Conflicting accounts
- One account places it “still embedded in the slope of the analogue mountain”; another has it flying “thousands of meters above the ground”, seen moving as a floating island. Whether these are two states of one object or two traditions is unknown.
- Whether it fell after the nexus burst or stayed aloft is disputed.
Open questions
- What makes it land or take off; what the crystal nexus is and how it relates to the gems.
- How souls are captured in a gem, and how many each holds; what the Central Tower is.
- What “dominion” requires for the Horseman’s title; who is the current master.
- Whether the custom of the gifted castle — “if a castle is given, every warrior… makes peace” — applies to the Prism.
In Vala
A wholly magical structure of quartz slabs amid the clouds, with knife-pointed towers, crystal gates, a courtyard, colored gem towers and many enchanted objects. Itineraries place it inside the citadel of the Knights of the Scar of the Sun.
At six in the evening, storytelling gatherings begin in which nations are classified. At the top, where the white light was, a crack appeared; what came out or went in is not recorded.
Conflicting accounts
- A flying fortress that serves as a prison.
- An embassy of demons and anomalous appendage of hell.
- A beacon of the gods fallen into Ardis Vala from an immortal city.
- One voice, only half trusted, says it was placed over the drow city of Zaira and destroyed its population.