Thaddium Fzort, son of Harmonious Fzort was the ninth king of the Entharion Dynasty. In 477 GUE, Thaddium became the heir apparent to the throne of Entharion. He succeeded Bozbo II in 481 GUE and ruled the kingdom from Largoneth for 64 years until 545 GUE. Since the settling of Antharia in 454 GUE, sporadic attempts by the Quendorans to set foot on Antharian soil prompted them to build a powerful navy that guarded the coast. This thoroughly irritated Thaddium Fzort, but like all the other kings of his time, he did not want to get his subjects riled and have to start an unnecessary war. He was also the one-time owner of the legendary Crocodile's Tear. Thaddium Fzort was succeeded by Mumbo I.

Many more details regarding this king were once found in "The Life of Thaddium Fzort" which was published by Froblivus.