During his stay in Wayrest, Helseth and his stepsister, Princess Elysana fought continuously on the issue of succession. This including the blackmailing of the Wayrest Councilor, assassination attempts, and many other strategies.
However, after the death of King Eadwyre, he lost the throne to Princess Elysana. Helseth and Barenziah were forced to leave Wayrest. They then went back to Mournhold, Morrowind and were accepted by King Athyn Llethan, the uncle of Queen Barenziah.
Through a clever move, Helseth took the throne of Morrowind after the death of King Athyn Llethan. It is rumored that Helseth was responsible for Llethan's death. An underground publisher released a book titled "The Common Tongue", a book that told the mass that Helseth was a subtle poisoner in Wayrest. "A Game at Dinner", a report by an unknown spy to a certain vampire lord, also related the story of Helseth and his cunning use of poisons.
At around the same time, the ancient goddess of Morrowind, Lady Almalexia opposed him. She knew that Helseth, with his cunning mind would take over Morrowind for himself, but she could not risk open war. Besides, she had lost most of her divine power due to her inability to reach the Heart of Lorkhan in the Red Mountain.
Then, the Nerevarine emerged. At first, Helseth saw the Nerevarine as another threat to his newly established monarchy. He hired the Dark Brotherhood to assassinate the Nerevarine. The Nerevarine proved to be mightier than any assassin the Dark Brotherhood could muster, and Helseth met the Nerevarine face to face.
Through clever manipulation, Helseth used the Nerevarine to turn the tide and eliminate all of the problems his new monarchy faced, allowing him to rule Morrowind undisputed.
- The Elder Scrolls III: Tribunal (First appearance)