"Danger and I are old companions."
A member of the Chironsala house, one of the oldest on Romulus. Not much is known of Keras's past before he held the rank of Commander and served as the commanding officer of the Gal Gath'thong, a Romulan Bird-of-Prey. A veteran of countless military campaigns, Keras was somewhat atypical, he believed that enough lives had been sacrificed for the Romulan quest for conquest.
Balance of Terror
"He's a sorcerer, that one! He reads the thoughts in my brain."
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.
"No. No, that is not our way. I regret that we meet in this way. You and I are of a kind. In a different reality, I could have called you friend."
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 was remembered by all Romulans as the Battle of Icarus IV. 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. In the aftermath of the defeat, Keras' family was disgraced.
They, under the command of his granddaughter Salatrel, would later seek revenge against Captain Kirk and the Federation, and were one of the forces behind the Romulan alliance with the Borg. Keras' son, Jannek, would become a diplomat who went to Deep Space 9. His other son Gaius would become Praetor of the Romulan Empire.
The name Keras comes from the Star Trek Customizable Card Game expansion The Trouble with Tribbles, and is an anagram of Sarek, as both characters were portrayed by Mark Lenard.