Cyrus is a cowardly and sinister one binome with a large black afro with a white streak. His allegiance shifted according to whichever side would be advantageous at the time.
Cyrus leads Bob and Dot Matrix to the secret meeting in Giedi Prime for discussion of liberating the sub-sector he lives in along with all the people there from Megabyte's control. Dot convinced the citizens of the sub-sector to give her their PIDs so they could be registered online with the Principal Office. Cyrus stole Dot's Organizer containing the PIDs and gave it to Megabyte to be decoded. Megabyte told Cyrus he would be rewarded by being named a lieutenant in his military. (Identity Crisis, Part 1)
Phong used a Reality Distortion Engine that caused Dot to see a version of the future where Megabyte takes over the sector. During her vision she discovered Cyrus' betrayal. After her vision Dot realized that Megabyte hadn't broken the security code to her organizer. She hacked into his systems and took back the file containing the PIDs. Dot then used a VidWindow to inform everyone in Silicon Tor that they had failed and claimed that Cyrus was in fact helping her side. Megabyte told Hack and Slash to take Cyrus to the PID extraction chamber, saying he needs a new shoe-shine droid. (Identity Crisis, Part 2)
Cyrus worked as a lowly shoe-shine droid for Megabyte for a year until the virus had a new job for him. He was ordered to spread propaganda against Guardian Enzo. Most citizens of Mainframe seemed to believe this propaganda. The young Guardian continued to fight for the city and win Games. (To Mend and Defend)
Cyrus stepped up his propaganda when he organized a 'Down with Enzo' demonstration. He gathered a small mob that became trapped in the Game while demonstrating against Enzo. They realized that Enzo and AndrAIa were their best hope to survive the Game. Cyrus was left with no choice but to help when accosted by AndrAIa. He rebooted as a Dick Dastardly-esque character, and drove a few vehicles in the Game. While attempting to survive, he managed to help Enzo by catapulting him onto the wing of the User's plane, then saved Enzo's life by catching him from a helicopter. After the Game ended Megabyte arrived to attack Enzo, he was unhappy with Cyrus' support for the young Guardian. Mouse's Ship flew by and dropped the last of a series of firewall senders. Enzo gave the command and the firewall activated. Just before it finished sealing off Giedi Prime, Hack and Slash grabbed Cyrus and quickly pulled him to their side as the wall closed. (Firewall)
Megabyte ordered Cyrus' execution, but Slash was unable to commit such an evil act and could not bring himself to delete Cyrus. He rescued him just before he was squashed by the pounding block. Slash then released Cyrus, and allowed him to run away. When Cyrus reached the firewall on the border of Giedi Prime he couldn't get out. He eventually noticed Scuzzy outside the firewall, who was trying to locate Hexadecimal. Cyrus suggested they could help each other. Scuzzy did make it to Hexadecimal's prison cell, so it is possible he did help Cyrus escape. (Game Over)
Dot's vision of the future where Megabyte conquered Mainframe and turned it into Megaframe showed what happened to Cyrus for betraying Dot. In this horrible future Megabyte ruled Megaframe with an iron fist, Enzo was a gang punk, and Phong was driven insane and was living in a box in an alley. Bob had been nullified in a Game and was living with Phong as a pet.
After talking to the insane Phong, Dot was chased down an alley by ABC security guards. They quickly called for Lieutenant Cyrus and cornered her at the end of the alley. A VidWindow appeared with Cyrus on it. He was wearing a viral uniform and the hat of an ABC Lieutenant. Cyrus told Dot they were there to help her and laughed cruelly. A Security Drone arrived and they all watched as it quickly shave her head and marked her with an identification bar code. Then the security guards and the VidWindow left, disappearing into the darkness, and the vision ended. (Identity Crisis, Part 2)