Gaius grew up with pride in his father, and joined the Romulan military academy hoping to please Keras by following in his footsteps.
In 2266, just as his father had been given command of a new starship, Gaius received a promotion to full serving rank, ahead of all his class mates, and pulled some strings to get himself posted on his father's new ship. When Keras returned home that night Gaius, in his new uniform, and his mother, waited to break the good news. Unfortunately Gaius was disappointed when his father outright refused to have him serve on the new ship, all too aware of the dangers the impending mission would entail.
The next day, just before Keras departed on the mission, Gaius met with his father again. The two settled their differences, with Keras making it clear he was very proud of his son and Gaius understanding his father's reasons for not allowing him to serve on the new ship. (TOS comic: "Alien Spotlight: Romulans")
As Keras feared the mission was not one he returned from, after taking the ghost ship across the neutral zone he engaged in a protracted battle with the USS Enterprise under Captain James T. Kirk and he and his ship were destroyed. (TOS episode: "Balance of Terror")
The furious Romulan Praetor ordered Keras' family put to death - Gaius and Arenn were brought before a firing squad, but stopped at the last minute when the Praetor had a change of heart brought about by the influence of his Klingon "allies" Korlat and Koloth. The Praetor then had a massive statue of Keras built to honor his heroic sacrifice - Much to the disgust of Gaius and Arenn, who knew Keras would have despised such idolization. Gaius vowed to serve the Empire for the honor of his father.
Gaius was invited by one of Keras' friends to serve under him on the ghost ship's sister ship. He boarded the ship in time to meet the Klingons for war games to test the cloaking device. Gaius was furious when one of the Klingons on board dropped his communicator to signal their position, allowing the Klingon ship to target the vessel. The Klingon retorted to Gaius' accusations of cheating that he simply did what was necessary to win.
Gaius continued to serve on the Bird-of-Prey, which about a year later was part of a fleet which apprehended the USS Enterprise in the Neutral Zone. Gaius saw through Kirk's ruse of having a corbomite device that would imminently cause massive destruction when he self destructed. But his commander was not willing to risk it being a bluff and ordered the vessel back off allowing the Enterprise to escape.
Gaius' ship returned to Romulus shortly after, and Gaius went to a bar to brood. There he was met by a pair of Klingons who talked to him about the recent mission and goaded him into a more vengeful mood. He decided to go home, but was shocked to find Imperial vehicles when he arrived - The Praetor was paying a visit. He was even more shocked, and appalled, to find the Praetor and his mother were due to be wed. (TOS comic: "The Hollow Crown, Issue 1")
Gaius reluctantly served with the the Praetor's honor guard at the wedding, and was further shocked to hear the announcement that he would be the Praetor's heir. His ascendancy came much sooner than expected, however: on their wedding night, Arenn assassinated the Praetor and then killed herself in an explosion caused by a Klingon bomb she had procured, in hopes of implicating them.
Kor and Koloth however, were able to convince the new Praetor that the brother of his father's centurion was behind the assassination, forestalling the dissolution of the Klingon-Romulan alliance. In his first public address as Praetor, Gaius announced that he would honor his father's memory by hunting down his killer, James T. Kirk. (TOS comic: "The Hollow Crown, Issue 2")
|Praetors of the Romulan Star Empire|
|primary universe||Pontilus • Sartorix • Colius • Comilius • D'deridex • Gileus I • Varus III • Karzan • Vrax • Gaius • Aratenik • Dralath • Darok • Narviat • Neral • Hiren • Shinzon • Tal'Aura • Gell Kamemor • Chulan • Taris • Sela|
|the Praetorate||Eveh tr'Anierh • Hloal t’Illialhlae • Ahrm’n tr‘Kiell • Urellh tr'Maehhli • Gurrhim tr'Siedhri|
|Kelvin timeline||Bervas • Decius|
The DS9 comic: "Blood and Honor" identified Keras' son as Jannek. However as Jannek was not present when the Praetor ordered Keras' family put to death he would seem to represent Keras' son of an alternate continuity rather than a brother to Gaius.