Guardian 452 and defender of Mainframe from both internal and external threats. Bob is often criticised by other Guardians for his unorthodox views regarding viruses: unlike other Guardians, who believe that viruses should simply be deleted on sight, Bob theorizes that viruses can be reprogrammed to live as Sprites (he cites Hexadecimal as proof of his theories). Despite this criticism, Bob is still respected as one of the finest Guardians ever to come out of the academy. Compared to Dot, he usually does things "on the fly", and is an extremely casual and laid-back hero in the first two seasons. After living and partially degrading in the harsh Web (under the alias Interface), he became slightly more cautious, more sensitive, and less impulsive than he used to be. Despite their difference in personality, he and Dot developed romantic tension that finally resulted in them coupling at the end of Season 3.

Dot Matrix

The daughter of leading Mainframe scientist Welman Matrix, Dot originally was his assistant as a teenager. Now an adult and proprietor of Dot's Diner, Dot also acts as her younger brother Enzo's surrogate parent and guardian since the loss of their father. (What became of their mother is never mentioned in the series.) She later became the command.com of Mainframe in place of Phong. She is admired for her brilliant and invaluable tactical skills, which led to her becoming a workaholic with business interests in most of Mainframe. Although she and Bob took until Season 3 to admit it, they are attracted to one another and this sometimes leads to awkward moments between them. When their father was nullified in the Twin City explosion, Dot and Enzo became each other's only remaining family, and for a long while she was adamant about keeping him from Games.

Enzo Matrix

Dot's little brother, Enzo, hero-worships Bob and intends to become a Guardian. He has a crackling, mid-pubescent voice and often uses catch-phrases such as "alphanumeric" and "high-density" in place of real-world utterances like "cool" and "awesome" to express enthusiasm. Enzo is very energetic and loves to play games like Jet Ball and Circuit Racing, and eagerly heads into the Games. Despite his youth, Enzo has proven to be extremely good at the Games and has several times been responsible for winning them.

With the destruction of the Twin City, most of Mainframe's Sprites were nullified and Enzo grew up with few friends to play with (it is unknown why he did not have Binome friends; presumably they avoided him because of his father's supposed role in the Twin City's destruction). His main friend growing up was Frisket until he met AndrAIa and brought her to Mainframe. The two have become inseparable since then.

When the Web invaded, Bob gave him a field rank as Guardian Cadet with the promise of sending him to the Super-Computer to be a real Guardian; when Bob was lost in the Web, Enzo found himself as the defender of Mainframe. He did well, gaining self-confidence and the approval of the populace, but eventually a Game came down he could not win, leading to his development into Matrix (see below). When Mainframe was rebooted at the end of Season 3, Matrix had accidentally left his icon in "Game Sprite" mode, causing the system to recognize Enzo as missing, and so created a second Enzo using the last available data on him: some time before "Talent Night".

Matrix

Adult Enzo Matrix, who, due to the dimensional difference of the game world (in the middle of season 3), aged quicker, making the time frame in the game world seem longer than it actually is. Ashamed of the child he used to be, whom he viewed as weak after his vicious defeat by the User Zaytan, he prefers to be addressed by his surname Matrix instead of his given name, which reminds him of his childhood. With a cold personality, violent behaviour and a "built-like-a-tank" physique (so physically built, in fact, that he was able to outmatch Megabyte physically in a fight), he is nothing like the child he used to be. He was tempered by what was from his perspective a lifetime of fighting. Although he is quick to anger he has still shown a desire to help those in need (albeit in a very gruff and violent way) and his quest to return to Mainframe has let him bring many systems back from the brink of annihilation. He harbours an unparalleled hatred towards viruses and will not hesitate to delete them in a violent and merciless manner. He is in love with AndrAIa, who has now matured as well, but is also quite jealous and protective of her. Deep down, he had a fear that he might become or already be a hate-driven, uncaring killer who had forgotten about his home and family and would end up like Megabyte; he had to face his fears and get past them in the hallucinatory Number Seven episode (based on The Prisoner). He would several times show an extreme temper, aiming a gun at Ray Tracer during arguments, and he instinctively raises his gun when surprised by something that might possibly be dangerous (including if he is bumped into).

AndrAIa

(Pronounced "and-RAY-uh") A backup copy of a Game Sprite who met Enzo in an undersea-themed game. She fell in love with him at "first sight." The original AndrAIa piggy-backed her icon on Enzo's. This allowed the backup to escape the game and stay in Mainframe with Enzo, but the original remained in the game.

Because of the nature of the game from which she was born, AndrAIa has many mermaid-like qualities: she wears fish-skin garments, wears starfish in her hair (which can be used like a shuriken with boomerang qualities), and utilizes such armaments as paralysis-inducing fingernails and a trident in combat. In her younger form, she was new to the ways of Systems and highly naive, not used to anything but fighting Users; over time, she began adapting and learning how to operate, and knew to try to keep Enzo's confidence up during his early days as Guardian. During the period of her and Enzo's journey through the Games in search of Bob and a way back home, she matures into a statuesque beauty who continually tries to temper her lover's cynicism, and provides a more relaxed and diplomatic counterpart to Matrix. It is also during this time when AndrAIa improved as a warrior and gained engineering skills.

Phong

System administrator and keeper of the core for Mainframe who lives and studies in the Principal Office. He was also the command.com (or as some believe, the assistant who does everything for the command.com who never makes an appearance). A wise old sprite somewhat evocative of Confucius, he often dispenses advice in the form of confusing and vague philosophical quotes gleaned from old README files. Very fond of Pong, one must defeat him in a game to be considered worthy of his knowledge. Phong is immune to infection by viruses, but not super-viruses (Megabyte was never able to infect him, but Daemon infected him quite easily). When the Viral Wars started, Phong was an invaluable aide and comforter to Dot. He was captured by Megabyte, decapitated (his head was later reattached), and had data extracted from his mind, but he refused to surrender and fought Megabyte to the last. One of his passwords was revealed to be "Yadda Yadda Yadda!"

Phong always has the right equipment or knowledge, often handy in whatever sort of situation; in one episode, Bob was shocked to find that Phong had prepared a countermeasure specifically to handle a giant monster made entirely of Nulls stomping around the city. He acts a wise therapist whom many come to for advice about their problems, but the majority of the time his advice isn't very helpful and he urges for sprites to figure things out on their own.

His name is a reference to phong shading. His appearance matches that of the output of a Phong rendering engine.

Hack and Slash

Hack and Slash are twin robots, identical in form except that Hack is red and Slash is blue. The pair originally served Megabyte, carrying out his orders, often in a very incompetent manner - their first appearance had Bob tricking them into crashing into each other. By Season 2, they had degraded in villainy to the point where they twice ask Bob for help (Bad Bob when trapped on a speeding Megatruck and Nullzilla after losing Megabyte's pet null) and also assist him in battling Gigabyte (saving him at one point). Hack and Slash have great physical strength. They once lifted and destroyed a very large bridge with ease in the episode Medusa.

Captain Gavin Capacitor

A software pirate and captain of the Saucy Mare, he styles himself as "the Crimson Binome".

Capacitor is a one-binome armed with a hook for a left hand and a peg leg in place of his right leg. He fits the pirate stereotype perfectly, complete with pirate catchphrase mutations such as "Shiver me templates!" and "By the code!" At heart, he is a romantic, driven at times by a sense of honour, comradeship and a desire to never go down without fighting.

He and his crew were only in the pirate game for the profit, raiding the Ports of Systems with lightning speed and co-ordination, but this ended when they arrived in Mainframe and Dot showed him that he could make more profit by legitimate business. Gavin then became a business partner of Mainframe until its Net Ports closed after the Web invasion. He did not get the chance to find new Systems to trade with, as Daemon took over and the Saucy Mare was forced to go on the run.

The pirates teamed up with Matrix, AndrAIa and Ray Tracer, entering the Web to find and retrieve Bob. From there, they returned to Mainframe and assisted Dot's rebels in the war against Megabyte. To Gavin's regret, he had to sacrifice the Mare in order to wipe out Megabyte's remaining airforce, and mourned its passing. After the System restart, he worked on unrevealed missions designed to harry Daemon.

His last name is a reference to capacitors. His first name is clarified to be a reference to ReBoot co-creator Gavin Blair (in the art book, he used Gavin Capacitor as his image, and all three co-creators had one character named after them in previous episodes). He was voiced by the late Long John Baldry.

Mr. Christopher?

Captain Capacitor's bookkeeper is a nerdy and timid zero-binome who's never seen without his laptop. His name is likely a tribute to Fletcher Christian, the Master's Mate from the HMAS Bounty.[verification needed] He may have also been named after Christopher Brough, president of Mainframe Entertainment.[verification needed]

Princess Bula?

A giant one-binome on Captain Capacitor's crew. Not actually a princess, but no one dares say otherwise. Mr. Christopher has a crush on her.

Miss Sally?

A female zero-binome pirate who serves as raider and look-out for the Mare. She once stole Glitch.

Mr. Andrew?

The one-binome pirate in charge of the steering wheel of Mare, who wears an eye-patch over his single eye. He was present during the search of Bob in the Web and at the Restart of Mainframe.

Mr. Jimmy?

A zero-binome who is in charge of the ship's prison.

Lens

Codemaster Lens appears in one episode ("High Code") of the original series, but is a pivotal character in the webcomic continuation.[2]

An insectoid figure, Lens is a Net-born member of the Codemasters, one of the most feared and dangerous sects in cyberspace. He came to Mainframe to challenge Codemaster Talon, who had taken refuge in Mainframe, but is known to the Mainframers as "Old Man Pearson". Amazed by the Mainframers determination to stand by Pearson, he left the System in peace.

Lens had a distinct code of honor, barely spoke to other characters, and was described as a terrifying hunter by Phong. Using his Gibson-Coil pike, he was able to teleport, knock over buildings, wield energy bludgeons, and imprison Bob's Keytool, Glitch, behind a force field. Lens refers to himself as belonging to "The 62nd Brotherhood".

He returns in the first issue of ReBoot: Code of Honor, initially as part of the Guild's delegation to meet the Guardians and reveal their Gnosis super-weapon. As with the other Codemasters, he wears stocky white battle-armour.

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