At some point before the events of Ryse, Commodus was appointed governor of Britannia and Basillius accompanied him to his new office. While Commodus focused more of his efforts towards military affairs, Basillius was left to manage political manners.
Like his brother Commodus, Basillius was incredibly narcissistic as a result of being brought up as the emperor's son, and he believed he could do anything he wanted in the world even if it meant causing great harm to others. While he was much more tempered than his brother, Basillius was still cruel and borderline sadistic towards those he deemed lesser than himself.
Basillius often neglected his duties, and instead indulged in a lavished life of comfort, sloth and lust. He regarded himself as a great artist, in contrast to his brother's need to destroy. However, a scroll found in Chapter VII reveals that Basillius often had great works of art stolen from their rightful creators and claimed them as his own creations to promote his own ego and delusions of grandeur.
Basillius appears for the first time in the closing scene of Chapter IV. As the XIV Legion led by Commander Vitallion arrives at York in the wake of halting a rebel assault on the city, Basillius greets the commander and his protégé Marius Titus at the city gates. With King Oswald and his daughter Boudica, the leaders of the revolting Britons, captured and at his mercy, Basillius exchanges words with Oswald and demands to know what has become of his brother Commodus, who was captured by Oswald a short time ago. When Oswald stubbornly refuses to cooperate, Basillius then turns his attention to Boudica. He briefly admires Boudica and states that she is beautiful, then callously orders his Praetorians to "Flog her until he talks, or she dies. Whichever comes first." Oswald cries out and Vitallion attempts to intervene only to be angrily scolded by Basillius who draws a dagger and proclaims that he does whatever he likes. Basillius then places his dagger to Boudica's throat and Oswald again bursts out and begs for his daughter's life. Oswald confesses that Commodus was traded to the Horned King of the north, and pleads with Basillius to release his daughter. After a moment's pause, Basillius appears to be moved by this plight and sheathes his dagger, then orders Vitallion and the Fourteenth northward to rescue his brother.
At some point after Commodus is rescued, he presents the captured Oracle to Basillius as a gift, and he takes her as a concubine.
The Fall of York
Basillius is not present during the peace ceremony between King Oswald and Commodus, and it is unknown whether he was aware of his brother's impending betrayal of the Britons. Regardless, after Commodus murders Oswald and an assault by the infuriated rebels ensues, Basillius and his brother are quick to board their armored warship and flee the city, leaving the populace of York and the Fourteenth Legion to die.
Tournament and Death
At an unknown amount of time after the fall of York, Commodus and Basillius return to Rome and Basillius settles back into his lifestyle, returning to his art and sculpting a grand marble statue of his father depicting the emperor. Meanwhile, Commodus masquerades as a false hero, and schedules a gladiatorial tournament in his own honor. Basillius hosts a small qualifying tournament for his brother's event in his brothel, which also contains a gladiatorial pit.
Upon learning of this, Marius Titus, having survived the fall of York and returned to Rome to avenge the betrayal of his legion, forges a disguise resembling the spirit of Vengeance Damocles and arrives at Basillius' establishment under the guise of a gladiator. As soon as he sees Marius in his disguise, Basillius is momentarily frozen in fear, believing that the actual spirit of vengeance has come for him. When Marius reveals himself to be a gladiator, Basillius' demeanor lightens, and he compliments Marius' armor.
Marius takes to the pit and faces 3 of Basillius' champions and a number of other gladiators to win his place in Commodus' tournament. Marius is showered in applause, and Basillius' praises, and is summoned to Basillius' chambers. There, Basillius compliments his skill as he hands Marius a scroll to admit him into Commodus' tournament, and goes on to state "You've turned killing into an art form". He then explains his own interests in art, and turns his attention to the near complete sculpture of his father. He enthusiastically describes how the head of the statue contains a secret compartment, and his plan to have it cry white wine to simulate tears. He then turns back to Marius and notes that it could be meant to cry anything, and after his says this Marius draws his sword. Basillius again freezes in fear and Marius runs Basillius through. As he collapses on the floor dead, knocking a bowl of a table in the process, Marius fills the bowl with his blood and fills the statue's compartment with it.
Later on, Basillius' statue of his father is fully assembled and moved to the throne room of the Emperor's palace. During the final moments of the siege of Rome by Boudica's hordes, Nero falls to his knees before his own statue and is horrified when it begins to shed Basillius' blood, and he runs screaming from the room and calling out for help.
A short time later, Marius Titus indirectly kills Nero by tackling him off a ledge at the top of the throne room and causing him to be impaled on the sword of the great statue that Basillius had made of his likeness, fulfilling the Oracle's prophecy that Nero would die by his own sword.