Mordea was the daughter of Celidia, a noblewoman whose parents had conspired to entrench their bloodline in Tenebrae's monarchy by arranging a forced marriage between their daughter and the lowborn Tempest known as Keldan. As she displayed competency in the arts of Tempestry, Mordea inherited the throne upon Keldan's death, and ruled Tenebrae thereafter as its harsh and unforgiving queen.
At the time of the Avatar's arrival on Pagan, Mordea had begun actively persecuting any who spoke against her regime. Those who opposed her were swiftly executed and thereafter had their bodies cast into the Sea of Rains, such as they might never fulfill their pact with Lithos. As a result of this practice, she earned the enmity of the Necromancers, and this feud had deepened to the point that she had actively disrupted the order's ability to perform rites by stealing their ritual dagger - quite nearly preventing the sacrifice of the dying Lothian.
In the midst of this oppressive atmosphere, the scholar Bentic had the misfortune to research Mordea's lineage, and discovered that her father, Keldan, had fathered a son with his first wife Ariel. He soon realized that this child (whom he identified as being the fisherman, Devon) would have inherited greater powers of Tempestry than Mordea herself, and that he should have therefore rightfully inherited the mantle of leadership.
Immediately after Mordea's agents learned of this discovery, Bentic was beheaded and Devon placed under arrest. On the eve of the fisherman's execution, however, the Avatar managed to discover Bentic's journals and learned of Devon's lineage - and although the hero was arrested and quite nearly killed alongside Devon, they managed to reveal the truth of his legitimacy to an assembly of witnesses. Mordea, enraged by the challenge to her rule, slew multiple bystanders with her magic and challenged her half-brother to prove his mettle. Devon responded by summoning magics which cast Mordea into the waters below the docks, where the tyrant found her death in the teeth of the Lurker's minions.
|“|| Ruler and Tempest of Tenebrae, our Lady Mordea governs with strict attention to detail. Her right of rule was inherited from her Tempest father, Keldan, and noble mother, Celidia - both royalty and real power support her claim to rulership. Our Lady is extremely aware of her position, accepting only the utmost in loyalty from her subjects.|
- Mordea cannot be killed by the Avatar in combat. Should the hero attempt to slay her, she will instantly slay them with a summoned lightning bolt.
- Orlok falsely claims that Mordea secretly frequents his tavern, and insinuates that he has bedded her.
- Bentic. Bentic's Journal (Ultima VIII - in-game).
- Vividos. Ethereal Software's Ultima VIII Transcript. Ultima VIII.
- Orlok. Ethereal Software's Ultima VIII Transcript. Ultima VIII.