Dykranus was born with bicephaly: he had two heads. He also contracted Encephalitis Lethargica, or sleeping sickness. Neither head was awake at the same time, though sometimes both slept at the same time. The weight of both heads constricted his facial artery, a condition that would eventually lead to insanity and death. His condition was hereditary, passed down by his mother.
He was raised like a son by Prime Minister Chak, as Dykranus' parents were busy running the government. He was kept from sight, however, and not even Starfleet Intelligence could provide images of him. He lived a sheltered life within a citadel known as the Cloister of Dykranus.
In 2274, he became imperator. Afterward, he made a "public" appearance by way of video. But by this time one of his heads had gone insane. While one of them loved the Federation and planned a 50th anniversary gala, the other threatened to secede. Conflicting messages to the Federation prompted a diplomatic visit by the USS Enterprise.
During an audience with a landing party from the ship, his insane head accidentally tripped and severed one of his heads with a blade of razor-sharp Locite-M. Leonard McCoy and Christine Chapel performed an emergency dichotomectomy. Dykranus began his recovery, thankful for a chance at a new life. (TOS comic: "Heads of State")
- Dykranus may have assumed the office of imperator as recently as one month prior to the story.