Keras held the rank of Commander and served as the commanding officer of the Gal Gath'thong, a Romulan Bird-of-Prey. Keras was somewhat atypical, having tired of war and conquest as a way of life for the Romulan people. He was a member of the Chironsala house, one of the oldest on Romulus. In 2266, the Praetor ordered the vessel commanded by Keras to cross the Neutral Zone and enter United Federation of Planets space. Keras was ordered to attack the Federation's defenses along the border, and gauge the response of Starfleet to this attack. Keras proceeded to attack and destroy several outposts in the area, attracting the attention of the USS Enterprise.
Captain James T. Kirk tracked down the Bird-of-Prey, and eventually managed to disable the Romulan vessel. Hailing the Romulan ship, Kirk and Keras spoke to each other briefly - the first time in history that a Human and Romulan had openly spoken to each other. While Kirk was willing to take on survivors from the Romulan ship, Keras refused, stating it was not the Romulan way. Keras committed suicide by activating his ship's auto-destruct systems. This would be remembered by all Romulans as the Battle of Icarus IV. Enterprise second-in-command Spock later told his father how much a striking resemblance the two men shared, giving more credence to the long standing theory about the Vulcan/Romulan genetic relationship.