Ditrius was a Klingon spy serving in the Romulan Star Empire's military.
By 2267, Ditrius rose to the position of Vice-Proconsul under Proconsul Toqel when she proposed the Klingon-Romulan Alliance. Ditrius would then assist her with setting up the alliance, including attending a meeting on Narendra III, but when Toqel was scapegoated for the attack on Theta Cobrini V he was promoted to the position of Proconsul. Afterward, as he escorted Toqel to her cell to await extradition to the Federation, he killed her as well as the guard in order to hide evidence of his treachery. (ST novella: The First Peer)