Characters of Halo

Recurring characters of Halo are organized below by their respective factions in the fictional universe. The multimedia franchise's central story revolves around an interstellar war between future humanity under the auspices of the United Nations Space Command or UNSC, and an alien theocratic alliance known as the Covenant. The artifacts left behind by an ancient race known as the Forerunner play a central role, particularly the massive weapons, dubbed Halos, built to contain the parasitic Flood. Beginning with developer Bungie's 2001 video game Halo: Combat Evolved, the franchise expanded to include the sequels Halo 2, Halo 3, Halo Wars, Halo 3: ODST and Halo: Reach; the novels Halo: The Fall of Reach, Halo: The Flood, Halo: First Strike, Halo: Ghosts of Onyx, Halo: Contact Harvest, and Halo: The Cole Protocol; and the Halo Graphic Novel, among other works.

In the foreword for a collection titled The Art of Halo, Bungie founder Jason Jones noted that bringing together the elements of a video game is unmistakably "art". However, Jones also noted that the character designers and artists had to make a "living, breathing world" and populate it with interesting characters and places. The game's development which spanned four years brought numerous evolutions and revisions to the character's designs and personalities. Characters were also updated to take full advantage of new graphics technologies; for instance, the Master Chief's armor was redesigned in a lengthy conceptual process and the final model was bump mapped. Each video game offered opportunities to refine the character's appearances and designs.

Halo's commercial and critical success has led to large amounts of merchandise featuring the franchise's characters to be produced. The Master Chief, the most visible symbol of the series, has been heavily marketed, with the character's visage appearing on soda bottles, t-shirts, and Xbox controllers. Other merchandise produced includes several sets of action figures, produced by Joyride Studios and McFarlane Toys among other manufacturers. Halo's characters have received varying reception, with characters such as the Chief, Cortana and the Arbiter well-received by critics, and Gravemind and Avery Johnson derided as clichéd or corny.

Character design and creation
Halo's characters were continually refined through development, as the company was bought by Microsoft and the platform shifted from the Macintosh to the Xbox. Other Bungie developers would often add input to the progress of characters in Halo, even if they were not working on the game itself. For example, an outside artist, Shi Kai Wang, developed the early concept sketches of what would eventually become the Master Chief. However upon developing a 3D model, the artists decided the Chief looked too slender, almost effeminate, and subsequently bulked up the character. Early Covenant Elites had a more natural jaw rather than the split mandibles they would later sport; at one point, Jason Jones was also insistent about having a tail on the Elites, but this idea was eventually dropped.

Designers decided to hand-key animations, rather than attempt motion capture. The animators also often videotaped themselves to have reference footage for the movement of game characters. Art Director Marcus Lehto had his wife videotape him "running around a field with a two-by-four" for footage for human marines. By Halo 3, Bungie staff had a special room designed for capturing reference material. Many of the subsequent human character's features were based on Bungie designers, while character animators looked to simian, ursine, insectoid and reptilian features for the various races of the Covenant. The artificial intelligences of the characters was also deliberately limited to make sure they acted realistically to environmental changes and situations.

Voice acting
The Halo series features voice work by television and film actors including Ron Perlman, Orlando Jones, Michelle Rodriguez, Robert Davi, and Terrence Stamp. Voice acting became more important as Halo: Combat Evolved's sequels were developed; Halo 2 had 2,000 lines of combat dialogue, while Halo 3 has in excess of 14,000 lines. The actual technology for the trilogy changed very little; while some actors voiced their lines in remote locations, others travelled to Bungie to record their lines. In interviews, Halo's voice actors stated that they had no idea that the games would become such a critical and commercial success. Steve Downes, the voice of the game's protagonist, stated that generally when a voice actor has finished their lines, their involvement with the game ends. As the characters in Combat Evolved were relatively undefined, the voice actors were given leeway to develop their own style and personality.

Aside from major character roles, members of the Halo community and Halo fans have had small roles in the games. The cast from the machinima Red vs. Blue won a lengthy charity auction for a voice role in Halo 3, and do a comedy routine which changes depending on the difficulty level the game is played on. Cast members of the defunct TV show Firefly—Alan Tudyk, Nathan Fillion, and Adam Baldwin—have roles as marines in Halo 3 as well as Halo 3: ODST.

Master Chief


Master Chief Petty Officer John-117, commonly referred to as Master Chief, is the protagonist and main playable character in the Halo trilogy. The character is voiced by Chicago disc jockey Steve Downes. One of the last of the SPARTAN-II supersoldiers still in active service (one of the few survivors of the Fall of Reach), the Master Chief inspires awe and fear in the alien Covenant, who see him as a demon. Assisted by the artificial intelligence Cortana, he prevents the firing of Installation 04 in Halo: Combat Evolved, an event which the player is told would have destroyed all sentient life in the galaxy. Bungie staff member Joseph Staten noted that until the Master Chief was created, Bungie had not paid any attention to how to make people want to play in the world. "Master Chief is really what kicked off the creativity," he said, "in terms of how people react to him. He's a space marine in really cool green armor." The character has since become a gaming icon, the mascot of the Xbox, and was rated as one of the greatest videogame characters of all time by Electronic Gaming Monthly.

Avery Johnson
Sergeant Major Johnson is a Marine who leads human forces against Covenant and Flood assaults throughout the Halo series. The character is voiced by David Scully. Johnson and a few other Marines survive the destruction of Installation 04 and are rescued by Cortana and the Master Chief during the novel Halo: First Strike. Johnson plays a much larger role in Halo 2, joining forces with the Arbiter to stop Tartarus from activating Installation 05. In Halo 2, he is awarded the Colonial Cross for his heroic actions, and leads UNSC forces to drive the Covenant from New Mombasa, Kenya after the Covenant take the city during the events of the game. In Halo 3: ODST, Johnson is seen asking an Engineer what the Covenant want in New Mombasa and the Engineer lit Johnson's cigar. In Halo 3, the Forerunner construct 343 Guilty Spark kills him when Johnson tries to activate the incomplete Halo at the Ark. Johnson is the sole character featured in The Halo Graphic Novel story, "Breaking Quarantine", which details Johnson's escape from the Flood in Halo: Combat Evolved, and a main character in the 2007 novel Halo: Contact Harvest. Johnson was said to have an immunity to the Flood due to his previous involvement in the Orion Project, also called the SPARTAN-I Project.

In many ways similar to the stereotype of charismatic black Marines found in other science fiction (such as Sergeant Apone in Aliens), some publications found Johnson, though enjoyable, somewhat of a flat character. In an interview for Halo: Contact Harvest, Joseph Staten of Bungie admitted that Johnson was a static character in Halo: Combat Evolved, and that despite the character's potential, "he sort of inherited those caricature aspects [from Halo]." Contact Harvest was a chance "to do right by Johnson, to give him the rich, fully fleshed out back-story he deserves, that we have never been able to give him in the game."

Miranda Keyes
Commander Miranda Keyes is the daughter of Jacob Keyes and Catherine Halsey whom she lived with in her younger years. Halsey and Miranda had a falling out in which she changed her last name (then Halsey) to her father's name (Keyes). Miranda appears in Halo 2, Halo 3 and in the final chapter of Halo: The Cole Protocol. At the beginning of Halo 2, Keyes is present at an awards ceremony on board the Cairo defense platform above Earth to accept a medal posthumously for her father. Soon after, a Covenant fleet launches an attack on Earth, and Commander Keyes links up with the rest of the fleet aboard the In Amber Clad and assists in the defense of New Mombasa, Kenya. When the Prophet of Regret retreats from Earth, Keyes orders the In Amber Clad to follow; this results in the discovery of Installation 05, another Halo. Keyes, along with Johnson and a squad of Marines, head for Halo's library in order to retrieve the activation Index and prevent the ring's activation while the Master Chief assassinates the Prophet of Regret; in the process, she and Johnson are captured by the Brute Chieftain Tartarus. As a "Reclaimer," only she or another human can insert the Index into Halo's control panel, and Tartarus attempts to make her to do this. When the Arbiter tries to stop the firing, Tartarus forces Keyes to insert the Index, initiating Halo's firing sequence. After the Arbiter engages and kills Tartarus, Keyes successfully removes the Index and prevents Halo from activating, but inadvertently causes all remaining Halo installations to enter standby mode, enabling the remote firing of these installations from The Ark. In Halo 3, Miranda Keyes returns to Earth and leads the pursuit of the Prophet of Truth through the portal he creates using the artifact buried under New Mombasa, which leads to the Ark. When Sergeant Johnson is captured by the Covenant to activate the installation, she attempts to rescue him; Keyes is killed when Truth shoots her in the back.

Miranda was voiced by Julie Benz in Halo 2, but Bungie recast the role for Halo 3, ostensibly because they wanted someone with an accent. Despite not being a part of Halo 3, Benz said that she loved voiceover work and that it was pure chance she had become the voice of Keyes in the first place. When IGN asked Benz what she thought of her character, she admitted she hadn't played Halo 2, even though Bungie had sent her "like four copies of the game". The character is voiced by Justis Bolding in Halo 3.

Cortana
Cortana, voiced in the games by Jen Taylor, is the artificial intelligence (AI) who assists the Master Chief throughout Halo: Combat Evolved, Halo 2, and Halo 3. She is one of many "smart" AIs, and is based on Dr. Halsey; the nature of her programming means she will eventually "think" herself to death after a lifespan of about seven years. Her actions during Halo: Combat Evolved help prevent the activation of the Halo installation. She escapes Halo along with the Master Chief in a fighter, and is instrumental in helping the UNSC survivors capture the Covenant flagship Ascendant Justice during the events of Halo: First Strike. During Halo 2 Cortana is put in charge of the MAC (Magnetic Accelerator Cannon) defense platform Cairo over Earth when the Covenant attack; she then follows the Chief on In Amber Clad to Delta Halo, where she further assists in intelligence work. Cortana stays behind on High Charity to detonate In Amber Clad ' s engines in case Halo is activated. She subsequently falls into the clutches of the Gravemind. In Halo 3, Cortana is rescued by the Master Chief from High Charity and aids him in activating the Halo ring under construction on the Ark. After narrowly escaping from Halo's destructive blast, she and Master Chief are stranded in space, awaiting rescue. Cortana was named the fifth best supporting character, and one of the "50 Greatest Female Characters" in a video game. Reviewers noted the character's determination and fearlessness meshed perfectly with the Master Chief, and that Cortana provides an anchor linking players to Halo's story.

Jacob Keyes
Captain Jacob Keyes (voiced by Pete Stacker) is a captain in the UNSC who appears in Halo: Reach, Halo: Combat Evolved, its novelization, Halo: The Flood, Halo: The Cole Protocol, and Halo: The Fall of Reach. His first chronological appearance is in Fall of Reach, where, as a young Lieutenant, he accompanies Doctor Catherine Halsey on her mission to screen possible SPARTAN-II Project subjects. In 2534, Lieutenant Keyes plays a pivotal role in saving a million insurrectionists' lives from Covenant forces. By 2552, midway through Fall of Reach Keyes is commander of the Iroquois, a UNSC destroyer. Keyes is promoted to Captain after he singlehandedly defeats four Covenant ships about to attack a human colony by performing a maneuver known as the "Keyes Loop". When the Iroquois is recalled to the human bastion Reach, a Covenant tracking device alerts the Covenant to the planet's existence, and proceed to attack the colony. As the planet is glassed by the Covenant, Keyes follows Cole Protocol, which leads his new ship Pillar of Autumn to Halo. There, Keyes leads a guerrilla insurgency against the Covenant, until he is captured and assimilated by the parasitic Flood in Halo ' s ninth mission, the eponymous Keyes. His daughter is Miranda Keyes. He also appeared in the Recent Halo: Reach at the end of the last mission, this is when he retrieves Cortana from Noble Six, and tells him "Good luck to you, Spartan".

Catherine Halsey
Dr. Catherine Elizabeth Halsey is a civilian scientist in the UNSC. She appears in the books Halo: The Fall of Reach, Halo: First Strike, and Halo: Ghosts of Onyx, as well as the Halo Legends shorts "Homecoming" and "The Package" and Halo: Reach. In the fiction, a flash clone of her brain tissue is the basis for the construction of the "smart" AI Cortana. As the creator of the SPARTAN-II Project, she is responsible for 75 of the 150 Spartan children, along with their training and the subsequent death of 30 due to the dangerous augmentation process. She is viewed by the SPARTAN-IIs as a "mother" figure, and addresses each soldier by their name rather than designation, even when the spartans are fully suited in their armor. Halsey justifies her actions through her belief that the suffering of a few is acceptable for the benefit of many. Sergeant Johnson, however, unknowingly causes Halsey to rethink her position, and she decides to "save each and every member of humanity beginning with herself" during Halo: First Strike. Dr. Halsey hijacks a shuttle for her own private mission to the planet Onyx; there, she assists in deciphering the surrounding Forerunner glyphs on the planet and leads the surviving Spartan-IIs and Spartan-IIIs to a Dyson Sphere at the heart of Onyx. She is later revealed to be the mother of Miranda Keyes.

James Ackerson
Colonel James Ackerson is a high ranking officer in the Office of Naval Intelligence, who has seen many years of service and has survived several battles with the Covenant. Such is his influence that he dominates the Security Committee and can talk down most higher-ranking officers without fear of reprisal. Due to the competition between Ackerson and other departments, most notably Section Three and the SPARTAN-II project, Ackerson harbors a strong resentment toward his opponents and toward the Spartans in particular. He does eventually convince the top members of ONI to approve his SPARTAN-III Program. In Halo: The Fall of Reach, he attempts to sabotage the MJOLNIR Mark V testing process by using ordnance far above the established guidelines, including Lotus anti-tank mines, a full squad of ODSTs ordered to shoot to kill, automated gun turrets, and an airstrike. However, Cortana retaliated by forging a letter requesting a reassignment to the front lines as well as planting evidence of illicit activities in his bank records. In Halo: First Strike, it is revealed that Ackerson manages to weasel his way out of Cortana's mess, In the limited comic series Halo: Uprising Ackerson falls into the hands of Covenant orbiting Mars and is slated to die before Ackerson tells his interrogator about a "key" to Earth. The "key" is in fact a fabrication by Ackerson to save a relative living in Cleveland, Ohio. After the Brutes holding Ackerson prisoner are informed that no such key exists, Ackerson is beheaded.

Franklin Mendez
Senior Chief Petty Officer Franklin Mendez is the SPARTAN-II's trainer on Reach during the early events of Halo: The Fall of Reach. He provides his trainees with excellent weapons and physical lessons, as well as tactical and mental training. He is not very talkative, but possesses a brilliant mind for warfare, and this is reflected in the Master Chief's abilities. He is described as neither tall nor muscular, with close-cut hair that has a dash of gray at the temples. He leaves the Spartans after the discovery of the Covenant to train the next batch of Spartans, and is recruited by Colonel Ackerson to assist Lieutenant Commander Kurt Ambrose (Spartan-II Kurt-051) with training the SPARTAN-III supersoldiers at the secret world of Onyx after a few years of combat duty (receiving two Purple Hearts in the process). During Ghosts of Onyx he is sealed inside the Forerunner Dyson Sphere at the heart of the planet with the remaining Spartan survivors.

Terrence Hood
Fleet Admiral Lord Terrence Hood (voiced by Ron Perlman) first appears in the novel, Halo: First Strike. He is a member of the UNSC Security Committee and is the Chief of Naval Operations. He greatly respects the Spartans, not only because of their record, but because they have saved his life on two occasions. When Halo 2 begins Admiral Hood presents the Master Chief, Sergeant Johnson, and Miranda Keyes with medals aboard the Cairo Station. In Halo: Ghosts of Onyx, Hood receives an urgent message by Dr. Halsey requesting for him to send Spartans to assist her, and obliges by ordering Fred-104, Will-043, and Linda-058 to Onyx. In Halo 3, Hood is in overall command of Earth's defense with Commander Miranda Keyes reporting directly to him. He accepts the need for humanity to ally with the Elites, but is not entirely happy about it. He leads the remaining human naval forces in an attack on the Prophet of Truth's dreadnought, but the attack fails when the Forerunner artifact under New Mombasa activates, creating a portal to the Ark. When the Master Chief, Keyes, and several Elite and human forces choose to follow the Prophet of Truth through the portal, he decides to stay behind to make a final stand on Earth. At the end of the game, he commemorates a small monument to the war and the sacrifices it involved.

Wallace Jenkins
Private Wallace A. Jenkins is one of many UNSC forces that survived the initial Covenant attack in Halo: Combat Evolved. Halo: Contact Harvest reveals that the soldier was a member of the colony Harvest's defense militia, where his family is killed. In Halo: The Flood, Jenkins assists in defending the human stronghold under the command of Major Antonio Silva. He is also part of an assault team led by Sergeant Avery Johnson and Captain Jacob Keyes, sent to recover a Covenant arms cache during Halo: Combat Evolved. The team is overwhelmed by the Flood, leaving the entire squad except Sergeant Johnson infected and resulting in the eventual death of Captain Keyes. In the video game, the Master Chief recovers Jenkins' helmet, and reviews the recording of the mission that it contained, introducing the Flood to the player through the Marine's eyes. In Halo, the fate of the Marine is left unknown.

Halo: The Flood reveals the fate of Jenkins; the Private is transformed into a Flood combat form along with the rest of his squad, but he is able to exercise a certain degree of control over the infection, due to the mind of the parasite being weakened by its long hibernation. He uses this limited control in an attempt to end his own life, charging at UNSC Marines in the hope that they would shoot him. Instead he is captured, as a live specimen for study. He is brought aboard the Covenant cruiser Truth and Reconciliation as part of a mission under Orbital Drop Shock Trooper Major Silva to capture a Covenant vessel and return it to Earth intact. Jenkins successfully convinces Lieutenant Melissa McKay, that such a mission would spread the Flood to Earth, and Jenkins dies with the other human troops on the vessel as it crashed into Halo.

Spartans
Conceived by Halsey, the SPARTAN-II project was secretly commissioned to create an elite corps of supersoldiers who could stem rebellion in the UNSC colonies; these soldiers became the best weapon against the alien Covenant when war broke out. While Master Chief is the hero of the trilogy, other soldiers play a significant role in the novels, Halo Legends and the prequel games Halo Wars and Halo: Reach. In an effort to raise morale as the war continued to sour for humanity, the existence of the SPARTAN-II Program is disclosed to the general public. The Spartans become heroes and veritable legends; in order to maintain public confidence that the war is going well, Spartans are never listed as killed, only as MIA or Wounded in Action (WIA).

The most distinctive element of the Spartans is their special MJOLNIR armor. The Mark V armor from Halo: Combat Evolved was ranked third of Casualty Gamer's "Top 10 Bodysuits", with the author commenting "It’s one of the most recognizable symbols from any game, and is literally the image of the franchise’s legendary hero, Master Chief." The "Recon" armor of Halo 3's multiplayer was also rated tenth of Machinima.com's "Top 10 Video Game Armor", as well as Maxim's.

Inspired by the Halo video game series, Troy Hurtubise, known for his anti-bear suits, developed a real counterpart to the MJOLNIR battle armor, named the Trojan. The suit is functional and its capabilities were inspired by those present in the video games versions of the armor. The armor's features include a system that purifies air powered by solar panels located in the helmet, equipment for weapon transportation, a recording system, emergency illumination and a transponder that can be activated if the wearer is in serious jeopardy. The armor offers protection against attacks with knives, blunt objects and small explosions and is bulletproof. Hurtubise expressed that he is able to improve this design for use in the military for a price of 2,000 dollars per piece. Non-functional replicas of the MJOLNIR armor have also been created by hobbyists; a Spike TV pre-Halo 3 special profiled some of these dedicated fans.

The High Prophets


High Prophets, or Hierarchs, are the supreme leaders of the theocratic Covenant. Upon assuming office, each Hierarch picks a new regnal name from a list of names of former Hierarchs, similar to the practice of some Orthodox Patriarchs. In Halo 2, there are shown to be only three; the Prophets of Truth, Mercy, and Regret (voiced by Michael Wincott, Hamilton Camp and Robin Atkin Downes. Regret is also seen in Halo Wars. In Halo 2, respectively; in Halo 3, Truth is voiced by Terrence Stamp). The novel Halo: Contact Harvest reveals that these three Prophets, originally known as the Minister of Fortitude, the Vice-Minister of Tranquility, and the Philologist, plotted to usurp the throne of the Hierarchs; in the process, they hide the truth that humanity is descended from the Covenant gods, the Forerunner, believing that the revelation could shatter the Covenant. During the course of Halo 2, Regret attacks Earth, and then retreats to Delta Halo. There, he calls for reinforcements, but is killed by the Master Chief. Later, Mercy is attacked by Flood on High Charity, and abandoned by Truth. In Halo 3: ODST, Truth is seen inspecting some Engineers around the Forerunner construct near New Mombasa. In Halo 3, Truth also meets his demise at the hands of the Arbiter when the Prophet attempts to activate all the Halo rings from the Ark.

Preliminary designs for the Prophets, including the Hierarchs, were done by artist Shi Kai Wang. According to The Art of Halo, the Prophets were designed to look feeble, yet sinister. Originally, the Prophets appeared to be fused to the special hovering thrones they use for transport; even in the final designs, the Prophets are made to be dependent on their technology. Special headdresses, stylized differently for each of the Hierarchs, adds personality to the aliens and a regal presence.

Arbiter
The Arbiter is a rank given to special Covenant Elite soldiers who undertake suicidal missions on behalf of the Hierarchs to gain honor upon their death. They are revered amongst the Covenant for their bravery and skills. In Halo 2, the rank of Arbiter is given to the disgraced former Supreme Commander of the Fleet of Particular Justice. Under his watch the Ascendant Justice was captured by the Master Chief and Installation 04 was destroyed. Rather than killing him, the Prophets allow the Commander to become the Arbiter, and to carry on his missions as the "Blade of the Prophets". Eventually, the Arbiter rebels against the Prophets and joins his fellow Elites in siding with humanity and stopping the Halo array from firing.

Originally to be named "Dervish", the Arbiter was a playable character intended to be a major plot twist by Bungie. Reception to the character was lukewarm, with critics alternatively praising the added dimension brought by the Arbiter as well as complaining about having to play as the alien.

In Halo Wars, set 20 years before Halo: Combat Evolved, a second Arbiter is shown, possibly as the last to wear the armor before the more recognized character. He is described as a "mean guy," lead designer David Pottinger comparing him to Darth Vader. The second Arbiter is the main antagonist of Halo Wars. He leads the Covenant to the fleet of Forerunner ships as well as capturing Ellen Anders in order to do so. After a fight he is killed by Sergeant Forge and a Spartan rolls his body off a cliff.

Rtas 'Vadum
Making his debut in Halo 2, the Special Ops Commander is never named in the game itself, leading to the unofficial nickname of "Half-Jaw" by fans, due to the missing mandibles on the left side of his face. With the release of the Halo Graphic Novel, however, the character was finally named in the story Last Voyage of the Infinite Succor as Rtas 'Vadumee. The character is voiced by Robert Davi.

'Vadum, originally 'Vadumee before the Covenant Civil War, is a veteran Covenant Elite and the second most prominent Elite character in the series after the Arbiter. The Last Voyage of the Infinite Succor explains how he loses his mandible; he is injured after fighting one of his friends, who was infected by the Flood. During the early events of Halo 2, 'Vadum serves as a messenger between the Hierarchs and the Elite Council, as he is seen relaying messages between the two parties in the Prophets' chamber; when the Elites split from the Covenant, 'Vadum joins his brethren in fighting the Brutes. In Halo 3, 'Vadum is Shipmaster of the flagship Shadow of Intent, and supports Cortana's plan to follow Truth to the Ark. Along with the Arbiter, 'Vadum leaves Earth to return to the Elite's homeworld with the end of the war.

Tartarus
Tartarus (voiced by Kevin Michael Richardson) is the Chieftain of the Brutes, easily recognized by his white hair, distinctive mohawk, and massive gravity hammer known as the "Fist of Rukt". Rough, arrogant, and disdainful of the Elites, Tartarus is completely dedicated to the Prophets' salvific "Great Journey". Halo: Contact Harvest reveals that Tartarus became Chieftain after killing his uncle (Maccabeus) and seizing the Chieftain's weapon. Tartarus makes his first appearance in the novel Halo: First Strike, as one of the first Brutes allowed into the chamber of the High Prophet of Truth. In Halo 2, Tartarus acts as an agent of the Prophets, branding the Arbiter for his failures. The Chieftain later appears when the Arbiter tries to retrieve the activation index of Delta Halo. On the Prophets' orders, Tartarus takes the Index and pushes the Arbiter to what was intended to be his death in a deep chasm. Tartarus heads to the control room of Halo with the Index in order to activate Halo, but is confronted by the Arbiter. Blind to the Prophets' deception about the Great Journey, Tartarus activates the ring; the Brute is ultimately killed by the coordinated efforts of the Arbiter with the help of Sergeant Major Johnson, successfully preventing the firing of Delta Halo.

Designs for Tartarus began after the basic shape and design of the common Brutes was complete. Artist Shi Kai Wang added small but distinctive changes to Tartarus' armor and mane in order to distinguish the Chieftain from the other Brutes. The visual design of the Chieftains was later modified for Halo 3, with the seasoned warriors sporting more elaborate headdresses and shoulder pads. In a review of the character, UGO Networks noted that whereas the Elites "are a precision scalpel", Tartarus was a "baseball bat" that smashes everything in its path.

343 Guilty Spark
343 Guilty Spark (voiced by Tim Dadabo) is the Monitor of Installation 04. He is the main antagonist of Halo Combat Evolved. He is first encountered by the player at the end of Halo ' s sixth level, "343 Guilty Spark", after the Flood breach containment. He enlists the help of the Master Chief, whom he calls a "Reclaimer", to activate Halo's defenses, neglecting to tell the Master Chief that Halo's "defenses" would cause the destruction of all sentient life in the galaxy. He attempts to stop the Master Chief and Cortana from destroying the Pillar of Autumn, and thereby destroying Halo, but is ultimately thwarted when the ship explodes and destabilizes his ring. Discovered in the system by the Covenant, Spark, known as an "Oracle" to the Prophets, eventually informs the Covenant Hierarchs of how to access Installation 05 in Halo 2. In Halo 3 Spark allies with the humans and Elites; since his installation has been destroyed and he has no more orders, Spark decides to help the Master Chief. Leading the Chief across the Ark, Guilty Spark discovers a new, uncompleted Halo, which is being built to replace Installation 04. Guilty Spark is ecstatic, but when Sergeant Johnson prepares to fire the new Halo to stop the Flood—a process that would destroy the incomplete ring and damage the Ark—Spark goes berserk, refusing to let the Reclaimers destroy "his" ring. He is subsequently destroyed by the Master Chief with a Spartan Laser, but Sergeant Johnson is fatally wounded in the fight.

Bungie originally wanted Spark to sound similar to the robot C-3PO. Dadabo noted in an interview that reactions to his character have been hostile, finding Spark highly annoying. He described Spark's character as a "bastard" who strings others along in order to accomplish his ends. An annual Halloween pumpkin carving contest named 343 Guilt O'Lantern is organized by Halo.Bungie.Org; both the contest's title and logo use the character's design and name as inspiration. Gaming site GameDaily listed Guilty Spark as one of the top "evil masterminds" of video games, stating "If HAL-9000 had any distant relatives, [Guilty Spark would] be closest of kin."

05-032 Medicant Bias
05-032 Medicant Bias ("Beggar after Knowledge" as revealed in Halo: Cryptum) was the Contender-class Forerunner AI and was charged with organizing Forerunner defense against the Flood. It was later defected by Gravemind turning in rampant and against Forerunners. It is first encountered in Halo 3 on the Ark, as it attempted to communicate with the Master Chief through Terminals, claiming it sought atonement by helping the Spartan.

Gravemind
Gravemind is one of the primary antagonists in the Halo series. The Gravemind is a large, sentient creature of Flood origin, created by the parasite to serve as its central intelligence once a critical biomass has been achieved. It was introduced during the events of Halo 2, where the creature saves both the Master Chief and Arbiter from their deaths, bringing the two face to face in the bowels of Delta Halo. Gravemind reveals to the Arbiter that the "sacred rings" are actually weapons of last resort; a fact the Master Chief confirms. In order to stop Halo from being fired, Gravemind teleports the Master Chief and Arbiter to separate locations, but also uses them as a distraction; Gravemind infects the human ship In Amber Clad, and invades the Covenant city of High Charity. Capturing Cortana, Gravemind brings High Charity to the Ark in an effort to stop the High Prophet of Truth from activating the Halo network. Although the Master Chief destroys High Charity, Gravemind attempts to rebuild himself on Halo. When Halo is activated, Gravemind is resigned to his fate, determined that the activation of the ring will only slow, not stop, the progress of the Flood.

Designed to be a massive, horrifying combination of tentacles and rotting matter, reception to the character was generally poor. Mike Leonard of the AllXbox community said that the introduction of the "Little Shop of Horrors" reject "ruined the 'cool'" of the Halo franchise. Jeremy Parish of 1UP.com complained that the link between Gravemind and the Flood was never explicitly stated in either Halo 2 or Halo 3 and was hardly seen in the last game.

Merchandise
The Halo franchise has produced numerous merchandising partnerships, and the characters of Halo have likewise been featured in a variety of products. The Master Chief, being the symbol of the franchise, has appeared on everything from soda to t-shirts and mugs. At one point, marketers for Halo 3 were planning on producing Cortana-themed lingerie. There have also been several series of licensed action figures produced, with the Halo: Combat Evolved and Halo 2 collectibles being produced by Joyride Studios in several series. For Halo 3, the responsibility of designing the action figures was given to McFarlane Toys; a total of eight series have been announced, with ninth series devoted to commemorate the tenth anniversary of the francise by re-issueing a few of the earlier figurines along with pieces to construct a buildable plaque of the Legendary icon used in the game for the hardest skill level. Kotobukiya produced high-end figurines. Besides general figures like Covenant Elites and Spartans, figurines produced include the Master Chief, Cortana, Arbiter, Prophet of Regret, Tartarus, and Sergeant Johnson.