Onk'ar Decath

Onk'ar Decath opening on Phlegethos

The Onk'ar Decath rift was created in secret by Asmodeus's most loyal confidants. It was built as a line of retreat if he had a falling out with the angels. He had reason to suspect he would because of his methods in dealing with the demons. In the Demon Spawn War, Asmodeus was for a time the supreme leader of all forces of the Quara'tun Covenant. Even though he was their supreme leader, his war practices on planes like Avernus and those of the Abyss were coming to attention of the more goodly angels and gods. These practices included torture, utter soul destruction, genocide against the demons, and putting non-demon allies in labor camps with often inhumane conditions. Spies had also learned that he was diverting souls destined to the Abyss and redirecting them to Baator where they were drawn into an illegally modified Well of Afterlife. The demon souls that were drawn here were changed in alignment to lawful neutral or driven insane in the process. The insane ones were still chaotic evil, and now in their maddened state too dangerous to keep around, so they were terminated. The sane lawful neutral ones were pressed into service and sent back to the battlefields of Avernus and other battle areas outside of the Prime.

At the time, the plane Baator was lawful aligned and not a Soul Gathering Plane. When Asmodeus became a Fallen Angel, Baator became better known as the Nine Hells, and became the soul gathering plane for lawful evil souls. It replaced Gehenna which had originally been set by Io as the plane for such souls. Io helped Asmodeus in this undertaking since not even Asmodeus and all the magical might of his followers could move the Well of Afterlife to Baator. Io's helping Asmodeus was done out of practicality since the angels and gods alone were not enough to counter the vast demon population of the 666 planes that made up the Abyss. When the work was done of making the Nine Hells the destination for the lawful evil souls, Asmodeus completed the deal by handing over the modified Well of Afterlife that he used in the Demon Spawn War.

 - Melek Taus, contract historian for Asmodeus - "Baator Deal"

When Asmodeus was cast out, the rift Onk'ar Decath was hidden with powerful magic. It was kept a secret by Asmodeus with him eliminating all those that had a hand in building it. Asmodeus used this rift to send agents to Bal-Kriav where they spread his influence surreptitiously. In the Horgon Era, he sent the tieflings through the rift where they built the settlement Kathodrarg. They built a temple to Asmodeus with the mouth of the rift as the altar. This transplanting of outsiders did not go unnoticed by the gods. Athena worked out a deal with Loki whereupon they sent agents into the temple who then planted a Null Mine inside the rift. When the mine detonated it permanently closed the rift.

In the Nine Hells, the rift is on Phlegethos. This side of the rift is still open, but goes nowhere. The rift's opposite end is on Bal-Kriav, in the labyrinths under Kathodrarg. Where the gate opening once was is now a Sphere of Annihilation locked in place by divine magic.

Filion'lyr

Filion'lyr

Filion'lyr was founded by drow colonists that came to Bal-Kriav from its parallel world Kriav. The drow came to Sygning by way of a Feydark Fissure. This fissure, a road between worlds, lies in a secure area of the city that grew up around it.

Filion'lyr is sited on a cavern ridge a hundred or so feet above the Vuzlyn river. A thousand yards northwest of the city is a tunnel through which this river flows. It spills out of this tunnel, plunging into a great falls that is illuminated in a rainbow of colors. These lights are from drow that use magic as a form of art. The Filion'lyr-Hlat'tar Tunnel was made in the city's last war with Hlat'tar's aboleth. The tunnel drained the lake that once covered much of Hlat'tar and brought an end to two aboleth city-states. This ended a period of three centuries during which the people of Filion'lyr were constantly under threat of aboleth attack or their conniving machinations.

Annbild's Entrail

Fire Snakes

Annbild Hrolmir, or Annbild's Entrail is a great lava river that courses across several regions of Brucrumus's Underdark. It was named after a legendary captain of the guard that served Surtur in the Dawn War. Surtur honored the death of this hero by naming one of the Great Vein's rivulets after him.

Annbild Hrolmir is a great river of lava that though immense in length is but an artery of the Great Vein of Surtur. The Annbild Hrolmir artery begins in the deepest reaches of the Underdark. Starting from the Great Vein, it pushes straight up for many leagues and then levels off becoming a eastward flowing magma river. When pressure is great enough from below, it causes eruptions at various points along the river. These areas have choke-points where the lava backs up until it can feed through submerged passages. In these areas is always an active volcano, while in areas of a dead volcano the checkpoint is gone from past eruptions, earthquakes or even the doings of something else.

The river begins in Sygning and flows eastward. Its first pressure release is the volcano Traeulf. After this volcano the lava river continues east for another four hundred miles where it splits off into two. It goes southeast into Ufthag and continues eastward across the bottom of Garathral. The split lava rivers feed all the volcanic activity of Agulbandal, and its four active volcanoes - Vaermund, Kradlod, Vistlod, and Trylming. Leaving Garathral, the lava river continues east, releasing gas and smoke up the Annbild Pipe and then cutting south where it feeds the lava tubes of Bolmod. In Yol Skerah, a region beneath the Aerie of Dragons, the lava river splits into three with each river ending at a volcano.

Annbild Hrolmir can be travelled by lava barge. It is not a normal route for most though because few can handle the often noxious and poisonous conditions, and extreme heat. The people of Surticon are the river's major traffickers. They use it move goods to distant ports from Sygning to Yol Skerah. Travel along the lava flow is stopped in areas where the lava completely fills the tubes. In these areas, a land journey is undertaken to move to the next open area where more lava barges are staged. Beyond the environmental hazard of the river, there are also bands of salamanders, fire snakes, and other fiery brutes.

The lava barges of Annbild Hrolmir, with their crews of fire giants, are the best protection against a hungry fire snake or salamander wielding a man-catcher.
 

 - Phoslomor, cartographer of the Third Epoch, excerpt from the book "Phoslomor's Survey of Midrêth, Ch. 6-2"