Rhiannon

Rhiannon is the name of a world which was once ruled by the warrior king Praecor Loth before it fell to the Guardian. It appears in Ultima Underworld II.

Description
Seven centuries before the Avatar set foot on Rhiannon, the realm was invaded by the Guardian's forces from the world of Killorn Keep, led by a young favorite of the Red Titan known as Thibris. In the resulting war, the Rhiannonian king, Praecor Loth, was shot and killed in the pitch of battle, and his queen, retainers, and servants followed him to the grave not long after. The Guardian's victorious servitors went on to rule the planet as part of their master's empire.

Fyrna
Fyrna is an icy region in the northern part of Rhiannon. It was the site of the last major battle of the Guardian's campaign, and it is here that Praecor Loth died.

Logris Mountains
In his final account of the construction of Praecor Loth's tomb, Eshka mentions the Logris mountains as a source of granite on Rhiannon.

The Tomb of Praecor Loth
Located in the steppes north of what was once Rhiannon's capitol, the Tomb of Praecor Loth stands as a monument to the world's last free king. Built by the master architect, Eshka, the crypt contains the bodies of Praecor Loth and his entourage - many of whom appear to have been buried with him shortly after his own demise. The interior of the edifice was fitted with a labyrinth of traps and snares to deter graverobbers seeking the treasures lain to rest with its chief occupant.

This was the sole location which the Avatar was able to visit through the facets of the Blackrock Jewel, and after their sojourn here, the hero discovered that the inhabitants of the tomb had been trapped in an undying limbo by perverse magics worked by Praecor Loth's three closest retainers, who had conspired together that they might convince the spirit of their lord that he still lived and reigned, and thereby maintain some pretense of their former glory. It would fall to the Avatar to free Loth of his delusions of life, allowing both him and his people to at last rest in the Void.

Inhabitants

 * Helena: former queen
 * Lethe: former general and lover of Praecor Loth
 * Lord Umbria: former court mage
 * Molloy: former tailor
 * Morphius: former spymaster and assassin
 * Praecor Loth: former king
 * Reef: former soldier
 * Silanus: former servitor of the Guardian
 * Trystero: former servant

Trivia

 * Rhiannon exists on a different plane than the world of Killorn Keep, and time demonstrably flows differently on the two worlds.