His father had been a "mere" baron, but was made Grand Duke after Princedom of Zebediah's fall to the forces of Hektor of Corisande. Tohmys inherited this position (retained only by Hektor's confidence) in turn.
Within less then a year, he started plotting with members of the Corisandian nobility to violently overthrow the Empire's rule in Corisande. The plot was foiled by the Imperial authorities with the aid of Merlin Athrawes. (AMF)
Following the discovery of his role in the conspiracy, Duke Tohmys was put under arrest in his palace to await trial for high treason. Once Empress Sharleyan arrived in March of the Year of God 895, the court convicted Symmyns, stripping him of all his ranks and titles and sentencing him to death. He was given access to a confessor, and later on the same day was beheaded and buried in unconsecrated grounds. (HFAF)