Ruidus (ROO-idd-iss)

Two moons hang in the sky of Exandria. One is Catha, a large, pale orb that cycles through its phases once per month. The other is Ruidus, a ghostly vermillion satellite that circles Exandria once every six months.
Catha's brightness is constant, its phases predicatable. Conversely, Ruidus exhibits strange behavior, seeming to glow more brightly at times or suddenly casting off its shadow to appear full. The vermillion moon does not wax or wane, and often disappears from the night sky entirely, while at other times it unexpectedly flares with bright, ruddy light.
Through a telescope, striations of Ruidus's vermilion hue and topography, which includes mountains, are visible. The moon appears to have an atmosphere, as stormy weather patterns with crimson clouds and light flashes are also visible through a telescope.

Folklore

In comparison to Catha, Exandrian scholarship does not know much about Ruidus; however, rising interest in Ruidus has led to the funding of new research. The origin of Ruidus's existence is unclear; some believe that it existed before the Founding, while others believe that the Betrayer Gods created it during the Age of Arcanum or the  Calamity as part of a lengthy but unknown plot that was abruptly halted by the Divergence.
Some stories say that during the Founding, a time when the gods still walked the face of Exandria, the world's divine creators discovered an unidentifiable power seeping through the fabric of reality. Legends assert that this alien influence was a threat to all life on Exandria, and the gods banded together to banish it.
This cancerous incursion of dark power is said to have crystallized into Ruidus. The gods agreed to create a tale about Ruidus to conceal its alien origin from the mortals of the world, informing them that it was a moon of ill omen, and its magical influence was always to be avoided. This tale concocted by the gods was not a lie, for Ruidus' alien magic twists the fate of those who are born or embark on ventures while bathed in its vermillion light.
Though Ruidus has its own power, some magic attributed to Ruidus actually derives from Alyxian the Apotheon.
Folklore across Exandria supplies the information regarding the symbolic association, religious significance, and phenomena connected to Ruidus. It is commonly believed across multiple cultures that Ruidus is an ill omen, and those born while it is bright are said bound for lives of ill fate. Some remote parts of Tal'Dorei  secretly sacrifice children born under a full Ruidus, partly as an offering to the dark moon and partly due to their belief that such children will suffer under a lifelong curse. The practice is banned in Tal'Dorei's cities. There is a prominent superstition that meteor showers are parts of a decaying Ruidus that have broken off and fallen toward Exandria.
Shortly after the discovery of a strange mineral in the sunken ruins of Cael Morrow beneath Ank'Harel by academics of the Allegiance of Allsight, members of the Consortium of the Vermillion Dream misattributed the mineral's origin to Ruidus and named it "ruidium" due to the resemblance of its red hue with the light of Ruidus. The color and properties of the mineral derive from magic which issues from the adjacent planar rift. Despite the misconception, the misnomer of "ruidium" remains the name for the mineral.

Ruidusborn

Individuals thought to be born under the light of Ruidus include:

• Alyxian the Apotheon
• The Raven Queen
• Warren Drassig

Scholarship

Scholars whose focus pertains to Ruidus are few. The Aydinlan Seminary in Yios, Marquet is associated with Ruidus studies, as evidenced by its resources on Ruidus in the Omen Archive and the faculty research activity of Kadija Sumal and Roe Estani.
The following are known to be scholars of Ruidus or whose research concerns Ruidus:

• Demid Sunlash. Sunlash identifies himself as "a studier of Ruidus".
• Kadija Sumal. Sumal and colleagues published a study on dreams with red storms. The authors hypothesized a correlation with Ruidus tidal corruption.
• Lumas twins, Balan and Zeyar. They corresponded with Roe Estani on astronomy, having learned of Estani through his publications. One year prior to their death, they took special interest in the sporadic flares of Ruidus. They were traveling to the Omen Archive at the Aydinlan Seminary in Yios to pursue their research but were murdered en route.
• Roe Estani. Estani's primary focus was on the intersection of planar and astronomical phenomena. In his later research, he observed historical inconsistencies relative to that intersection and accounts of extraplanar travelers which led him to focus on Ruidus. He did not publish his later findings on his theories regarding Ruidus. He had some crossover with Sumal during his tenure at the Aydinlan Seminary.

Extraplanar phenomena

Members of the Allegiance of Allsight below Ank'Harel in the 830s PD discovered a gaping planar rift that pulsated with sickly red light, known as the Netherdeep. The myth of Alyxian connects the origin of the Netherdeep with his interposition between Gruumsh's spear and the city of Cael Morrow during the Calamity. An extant version of this myth holds that "the Apotheon's connection with Ruidus flared to life" at the moment of his interposition.
Some worry that rare double eclipses, where Catha and Ruidus simultaneously overlap the sun, cause the Material Plane and other planes to calamitously intersect.

Type

Planetoid / Moon