Sen Dunsidan is a character in The Voyage of the Jerle Shannara and High Druid of Shannara trilogies. Based in the Southland city of Arishaig, he was the ambitious Minister of Defense for the Federation who rose to the position of Prime Minister with the help of multiple villainous allies.
Sen Dunsidan was Minister of Defense for the Federation for about fifteen years. Outwardly he seemed to be mild, detached, and a good observer, a man eager to make everything right for everyone. In reality, Dunsidan had the morals and instincts of a snake. He knew that the way to survive was to keep his preferences and ambitions secret. He was clever, patient and thorough, with a legendary work ethic. He desired absolute power over everything and everyone.
Sen Dunsidan acted as both an ally to and spy for Grianne Ohmsford, the Ilse Witch. As a man high up in the Federation he was the ideal person to do her favors, in exchange for favors she could do for him. If she showed him ways of achieving his goals he would do anything she asked. Unlike the rest of her spies, he considered himself her equal—his pride and ambition would not allow anything else.
Dunsidan also formed a partnership with the Morgawr, the Ilse Witch's master. In exchange for making Dunsidan Prime Minister, the Morgawr requested the use of enough airships and crew to enable him to pursue the Ilse Witch on her journey to Parkasia.
Dunsidan led the Morgawr to Arishaig's prisons to fulfill his part of the bargain by supplying crew members for the Morgawr's voyage. With the assistance of the Turnkey he approached the prisoners and offered them a chance to leave the prisons.
As the prisoners were released one at a time by the Turnkey, the Morgawr used magic to penetrate their heads with his hand so that he could feast on their souls. One by one, the Morgawr turned each released prisoner into a walking dead man, a shell with no will of its own. Over the course of two nights, the Morgawr converted over 250 imprisoned men into living puppets. The Turnkey, horrified, committed suicide the first night, forcing Dunsidan to bring the prisoners to the Morgawr himself the second night. After the Morgawr took the men away, Dunsidan never saw any of them again.
The morning after the Morgawr finished gathering his crew and left, both the sitting Prime Minister and Jaren Arken, Dunsidan's main rival for the position, were found dead. Dunsidan was now Prime Minister.
During a battle between the Federation and the Elves on the Prekkendoran Plains, Dunsidan succeeds in wiping out the Ellenroh, the airship of the Elven King Kellen Elessedil, using a prototype of a devastating diapson crystal-powered, fire-launching weapon. The resulting conflagration kills Kellen, his two sons Kiris and Wencling, and the entire airship crew.
Pied Sanderling, Captain of the Elven Home Guard, successfully rallies the demoralized remainder of the Elven army to repel the advancing Federation forces and take refuge in a besieged Free-born camp. He leads a daring raid on the Federation base and manages to destroy the Dechtera, the airship that was carrying the deadly prototype weapon.
Unshaken, Dunsidan commissions the building of another such weapon. Meanwhile, he continues to reject the advice of his newest ally Iridia Eleri. Iridia wants him to attack Arborlon, the Elven capital, to subjugate the Elves once and for all.
Dunsidan finds out too late that Iridia is actually dead and possessed by the Moric, a Demon who was brought out of the Forbidding and into the Four Lands by the liquid night in exchange for Grianne's banishment into the Forbidding. Dunsidan and his weapons engineer Etan Orek are both killed by the Demon, which takes the Prime Minister's form by inhabiting his body.
The Moric, in the form of Sen Dunsidan, takes Etan Orek's newest weapon upon the airship Zolomach towards Arborlon. Its intent is to destroy the Ellcrys, the only barrier keeping the Demons of the Forbidding from flooding the Four Lands.
Sen Dunsidan is tall and athletic, with a strong face and silvery hair that hangs loose about his shoulders, except where it is braided above his ears in keeping with current fashions. He is an attractive man with a magnetic personality, until one gets to know him.