The Achaean sun, sometimes referred to in literature as Helios or Sol (from which the possessive form "solar" is derived), is a vast star composed of elemental fire and pure life energy not unlike that harnessed by unicorns and phoenixes. This celestial body forms the centre of our solar system, of which only four planets past and present have been identified: Noxtra, Somnustra, Lunastra, and Achaea. Many other planets are known to exist and have been observed by scientists, though their names and natures remain a mystery. Today, only Achaea remains; the first three were destroyed in the saga known as the Eternal Night. Though the sun is thousands of times larger than our planet, its size pales in comparison to other stars such as the now-destroyed Ethian.
As a primary source of life energy and light, the sun is vital to nearly all living things on the face of the planet. Its warmth allows for the temperate climate that Sapience enjoys, and its light helps the various green plants of the land to thrive (including the Groves of Druids and Sylvans), which in turn feed other creatures.
The ruins of a subterranean temple dedicated to the solar spirits is located at the top of the small peak below Mount Luth on New Hope.
The occultic art of Tarot includes the Sun tarot, a card which provides light in dark places.
Each of the ten distinct phases of the Achaean day observable to attentive sky-watchers.
- Late night
- The night begins to wane, giving way to the swift approach of dawn.
- Considered the beginning of the solar cycle; the glow of the sun first appears from the eastern horizon during this phase. A time of waking for diurnal plants and animals of Achaea, visible in Eleusis. It is also considered holy by priests and paladins, inspiring revitalised devotion and rites of prayer. Some cities mark the beginning of day with activity, such as the chimes of the city clocktower in Cyrene. Dawn is brief, before the rising sun brings morning.
- The sun rises higher, fully casting off the shackles of night.
- Late morning
- The transition from morning to mid-day.
- The height of day, the solar orb reaches the pinnacle of the vault, banishing all shadows. The Cyrenian clocktower chimes joyously at noon, celebrating the sun's zenith. Noon is brief, before the sun begins its descent into the afternoon hours.
- Early afternoon
- The hours turning after noon are gradual and sultry.
- Late afternoon
- A slight darkening of skies and lengthening of shadows. Sunlight filters past Achaea's three rings, reflecting silvery sparks off of the second.
- The skies burn with sunset colour even as it darkens with the onset of night.
- Deep night
- When darkness rules the land. Retreating daylight brings the moon and constellations into full visibility. Achaea's outermost ring glitters pale with moonlight.
- Deepest darkness, the middle of the night marks the turning point of a new calendar day.
Exploring of the planar highways of Yggdrasil, Achaeans discovered the existence of other suns wheeling through the skies of other planes. The plane of Veior for instance, has three suns, whilst the plane of Drauger has as many as six observable at a time.