A setting-specific variant on Contact Outer Plane.
Oceana is a planet (and a god), mostly ocean (60%), at the center of nested spheres. Not quite eight thousand miles in diameter, with 200 million square miles of surface (only about 60 million of usable land, however). The world is said to be hollow with a nested sphere deeper within, although estimates of size vary.
The Blue Maze orbits 8 thousand miles above, and is 320 miles in diameter (it appears about five times as wide across as Earth’s moon).
The Great Eye orbits 11 thousand miles above, and is 97 miles in diameter (it appears about the same size as Earth’s moon). In recent memory, the iris has never been focused anywhere on Oceana, but is always just a little off-center. It is said that anything within a few miles of the surface of the moon is attacked by mile-long tentacles, storm winds, random spell effects, and a corrupting aura.
The Sun is set into a solid ring of pure adamant that orbits 24 thousand miles above. The ring is said to be 216 miles wide, 6 miles deep, and 200 thousand miles long, with a gap for the sun. The surface is freezing everywhere except near the sun.
The Outer Sphere is a vast sphere of adamant with no apparent egress, 56 thousand miles above. Reflective surfaces along the inner shell reflect sunlight back, forming stars.
In the space between the bodies, there is very thin atmosphere—even thinner than that of very high terrestrial altitudes—which prevents the use of wings, lifting gases, or similar non-magical flight. And while it is breathable, creatures who require oxygen will be weakened after an hour spent in it (double the effective weight of gear, halve move, and –2 on melee attacks and damage). They recover after an hour in normal atmosphere.
Contact Outer Sphere
This fifth-level arcane spell puts the caster’s mind in contact with an entity from one of the outer spheres and pushes it to answer questions. There are said to be still other outer spheres that a caster could contact, but little is known of them, and most rumors imply that it is better to avoid them entirely. The list below are the closest thing to a "dependable" list:
The Blue Maze
A crystalline entity of sharp edges and cold-blooded logic, as often malevolent as benign. Lore states that they think in maze-like terms, and may lie for a greater good, or simply to fit the “pattern of events.”
Blue Maze entities never answer more than three questions, and their answers are often riddles or enigmatic one-word replies. When the question is asked, make a proficiency throw 16+ to know it, and roll 1d6: on a 4+, the entity lies undetectably.
There is a 5% chance per casting that the caster will become utterly lost in a riddled answer for 1d6 weeks, obsessed with it and unable to think of or do anything else. Casters of at least 11th level are immune.
It is possible to deliberately choose a more powerful entity in the Blue Maze. Each step more powerful grants a +1 on the proficiency throw, increases the chance of insanity by +5%, and increases the minimum caster level for immunity by +1.
The Great Eye
A malevolent and horrible wisp of pure Chaos . . . which nonetheless may know something useful by chance.
Chaos wisps answer 2d6 questions, always with a single random word. Make a proficiency throw 13+ for the word to be relevant; and roll 1d6: on a 5+, the word is relevant, but a lie.
There is a 20% chance per casting that one of the random words produces a sense of growing horror and nightmarish terror in the caster’s unconscious. If so, the caster is fine for 1d6 days . . . and then loses 2d4 weeks to catatonic fear.
Each level above 11th reduces the number of weeks of insanity by one.
Because of the similarity in the nature and scope of the insanity, many believe that the spell oblivion sends its targets to some part of the Great Eye.
A monstrous titan whose soul is trapped in the adamant ring holding the sun in place. It’s knowledge is ancient and terrible.
An adamant titan soul will answer eleven questions, each with a Word of Power which illuminates the path to knowledge. Make a proficiency throw 5+ for the titan to know the answer; and roll 1d6: on a 6, the titan has chosen to lie for its own obscure purposes. This lie is undetectable.
There is a 95% chance (minus 5% per caster level) that one of the Words spoken by the titan will drown the caster’s mind in what feels like a few seconds of imagery and knowledge . . . but takes the caster a full season to assimilate. While assimilating the knowledge, the caster is paralyzed and must be cared for by others.
Within the Sun lies a fire elemental of unsurpassed power, bound there by Oceana to serve her purposes. The Sun elemental knows all things that occur on the surface, in the light, or in even the faintest warmth, on Oceana and the other spheres. The Sun is Oceana’s eye on the world.
The Sun elemental will answer up to twelve questions, so long as all twelve questions are on the same general topic, and will answer with reasonably complete sentences.
The proficiency throw is 2+, but if it occurred in the physical world, the Sun automatically knows the answer. The Sun does not lie.
There is a 50% chance that communicating with the Sun will temporarily blind the inner and outer sight of the caster, leaving him blind, babbling, and unable to cast spells for two entire seasons.