c. 100,000 BCE (original body)
Approx. 1.67 meters (5 ft 6 in) 
Mind used as basis for 343 Guilty Spark
- "A long time ago, I was a living, breathing human being. I went mad. I served my enemies. They became my only friends."
- —343 Guilty Spark reminiscing his original form.
Chakas was a hamanune living on Earth in approximately 100,000 BCE. After a rough youth on Erde-Tyrene, he became a prominent player in the Forerunner-Flood conflict and the Librarian's plans due to a geas the Lifeshaper had imposed on him. Although his physical body was eventually killed, his mind survived in the form of the Forerunner monitor, 343 Guilty Spark.
 Early life
Chakas' family had a farm outside the city of Marontik, but after his father was killed in a knife fight with a water baron's thugs and the family's crops failed, they moved to the city. There, he took up several menial tasks to make a living while his sisters went to serve as Prayer Maidens in a temple dedicated to the Lifeshaper.
During his life in Marontik, Chakas enjoyed getting into fights and stealing, and was feared by many. He also began having dreams of meeting a Forerunner and then attacking and robbing him, in hopes of selling his "treasure" and using it to bring his sisters back from the temple to live with his family. Chakas, at the time barely twenty years old, was then visited by Riser, a Florian, who offered him work and guidance if he stopped getting into trouble, saying that he had seen someone like him in a dream. Chakas accepted, and Riser showed him various places where he could find useful work. Chakas also provided protection to Riser's clan, which in exchange fed Chakas' family.
 Meeting with Bornstellar
When the Forerunner Manipular known as Bornstellar Makes Eternal Lasting arrived in Marontik, Chakas and Riser were serving in a collective of guides. After the Manipular enlisted their aid in his quest for Precursor artifacts, the two humans joined the young Forerunner on an expedition to the Djamonkin Crater, where Bornstellar found the Didact's Cryptum. Here, thanks to a geas implemented by the Librarian, he along with Riser sang a sound code, programmed into their geas, that authorized the opening of the Cryptum. This awoke the Didact, whom they later followed on his ship first to Charum Hakkor and later to Janjur Qom, the San 'Shyuum homeworld, in the hope this would spark a memory imprinted by the Librarian that could help the Didact. On the way, they also began discovering memories of their ancestors who fought in the Human-Forerunner War, imprinted as part of their geas. On Janjur Qom, Chakas was imprisoned by the Master Builder along with Riser and the Didact.
 Odyssey on Installation 07
Later, the ship carrying Chakas was caught in the massive battle around the Forerunner capital and destroyed. Chakas, accompanied by several Forerunner guards, fled in an escape pod which made a rough landing on the surface of Installation 07, one of the Halos under control of the rampant AI Mendicant Bias. Injured, Chakas was discovered and tended to by a human girl known as Vinnevra, from whom Chakas learned that the Halo was home to various species and subspecies of human, who collectively referred to themselves as the "the People". Many of these humans had been transplanted on the ring long ago by the Librarian, while others had been brought in more recently by the Master Builder, who used humans in his cruel experiments on the Flood.
It was here that the consciousness of Forthencho, the Lord of Admirals, who had commanded the human military forces against the Didact's fleets in the final battle of Charum Hakkor, surfaced alongside Chakas' own mind. After Chakas had recovered, Vinnevra took him to see her grandfather, Gamelpar, who explained that he was also born on Earth and, like Chakas, held an "old spirit", or ancestral personality imprint, within him. Vinnevra then began to experience an urgent need to travel to where she assumed it would be safe; this was actually due to a geas imposed on the humans born on the Halo. Chakas, hoping to find Riser, joined Vinnevra and Gamelpar as they decided to leave the village and follow Vinnevra's geas. As they approached their destination, however, they discovered that Vinnevra's geas was leading them to what the humans called a Palace of Pain; a Flood research station where the Forerunners conducted experiments on humans. Observing the facility from a distance, Chakas, Vinnevra and Gamelpar witnessed numerous humans being herded into the structure by the Primordial, supposedly the last Precursor. Horrified, the three then decided to move in the opposite direction. Arriving at the shores of a large lake, they came across an abandoned human city. Exploring the city, Chakas and Gamelpar discovered a proto-Gravemind imprisoned in a Forerunner energy cage, and promptly left.
After crossing the lake, the three were found by a Lifeworker named Genemender Folder of Fortune, several Denisovans, and a large ape known as Mara and taken to a village full of humans. Upon being fed by Genemender and sent to sleep, Chakas was awakened by Riser, who warned him not to trust the Lifeworker and the other humans. Soon after, Genemender took Chakas to his hidden base of operations and revealed that the humans in his compound were not actually alive, but archived personalities manifested as realistic hard light holograms and stating that he was under orders to salvage the humans' genetic records to prevent them from falling into the hands of the Flood and the Master Builder. Genemender proceeded to do the same with Chakas, who upon realizing this attempted to attack the Lifeworker, only to discover that Genemender was also merely a hologram based in a monitor; he had archived not only the humans in the village, but also himself. As Chakas returned outside, he discovered that Gamelpar was dying. Genemender stated that they should salvage the personality imprint the old man carried, but Gamelpar adamantly refused, instead wanting to die with dignity. Chakas then accompanied Gamelpar him in his final moments, with the old man having Chakas promise to watch over Vinnevra.
The entire area then experienced a power outage, powering down the monitors and the holograms of the archived humans. As Chakas, Vinnevra and Mara moved on, Riser joined them, having observed them from a distance for some time. Chakas was joyed to reunite his friend, who then proceeded to explain how he had stumbled upon them. The two also allowed their "old spirits" converse with one another; it turned out that Riser carried the consciousness of Yprin Yprikushma, who was once a political opponent of Forthencho. After the two ancient humans had finished their exchange, Chakas and the rest of the group continued their journey, directed once again by Vinnevra's geas. Starving and exhausted after traveling for several days, they eventually came across a rail transport and boarded it. The transport took them to a Lifeworker research station, where they were instructed to enter a boat-like vehicle with an uncertain destination.
The transport took them deep within the interior of the Halo, all the way down to the lair of the rampant AI Mendicant Bias itself, where many more humans had been rounded up. There, Chakas had his mind thoroughly scoured by the AI, in an agonizing process which made him lose all perception of time and place and forcing him to live through countless fabricated dreams, including journeys across the Halo over and over again. Eventually, Chakas' and the other humans' ancient personality imprints were brutally removed, causing them severe physical and mental trauma. The humans were then rounded up by Mendicant Bias, who offered them the choice to help it fight its former masters with their "old spirits", who had been placed into monitors. Their first task was to save the Halo from an impending collision with a planet; the Halo had been programmed to enter a destructive course as a security measure should it fall in the wrong hands. Though Chakas was hesitant, Forthencho lied to Mendicant Bias that he had accepted, and the two were taken to the Halo's Cartographer facility to interface with the Halo's controls and help coordinate its movements.
As the Halo approached the planet, a fleet led by the Didact suddenly appeared, and the Didact immediately disabled Mendicant Bias with a failsafe code. He then entered the Cartographer and aided Chakas in controlling the Halo as it moved past the planet. The ring took heavy damage but eventually survived; the Didact commanded that the Halo first shed its most damaged parts and then be moved to an Ark installation for repairs. As the Halo began its passage through the slipspace portal, Chakas went unconscious.
 Rebirth as a monitor
- Main article: 343 Guilty Spark
Some time later, Chakas awakened to find himself in a life-support system which sustained his mortally wounded body, accompanied by the Didact. The Didact explained that Chakas' body would not recover from the trauma inflicted by Mendicant Bias' extraction of his imprint, but that his mind would be salvaged and converted into a monitor. Forthencho and numerous other ancient human personality imprints, as well as records of the Librarian's various experiments, would also be stored within this construct. While the conversion process was still underway, the Didact took Chakas with him to the bowels of Installation 07 as he interrogated, and eventually executed, the Primordial. Soon after, Chakas' physical body was disposed of and he began to serve the Forerunners in the form of a monitor, later to be known as 343 Guilty Spark.
Assigned as the caretaker of Installation 04 near the end of the Forerunners' war with the Flood, 343 Guilty Spark would again encounter humans during the Battle of Installation 04 late to the Human-Covenant War in 2552. He continued to interact with the Reclaimers until he was severely damaged by John-117 in the endgame of the Raid on Installation 04B, but never revealed his nature as a former human being.
Between 2553 and 2557, the severely damaged remains of Guilty Spark were recovered from Installation 00 by a UNSC science team and taken aboard the UNSC Rubicon. The science team proceeded to query the ancient human on the Didact and the historical nature of Forerunner-human relations. The damaged monitor then told the humans the story of his life and how he was transformed into a monitor. While telling his story, the monitor constantly made breaches through the ship's firewalls, in order to access the humans' historical and palaeontological records, which greatly frustrated and distressed the UNSC personnel. After the monitor had finished, it shut down completely and was ejected into space by order of the ONI team commander. However, Spark had inconspicuously transferred his data stream into the ship's system, and soon took over the entire ship, planning to use it and its crew in his quest to find the Librarian, who he claimed to know was still alive after examining and studying her fate for the last 100,000 years.
When first meeting Bornstellar, Chakas was apparently enthusiastic about mysteries and searching for treasure. Chakas did not seem intimidated by Bornstellar at first, but somewhat resentful for dragging him into the adventure later on. Inspired by his dreams, he actually planned to trick the Manipular and rob him when the opportunity presented itself, but later found that he and the Forerunner were much alike and could not bring himself to hurt him. On the long run, he did not appear to be upset with Bornstellar, and he was said to have changed very much since leaving Erde-Tyrene, especially after examining the memory imprints of his ancestors.
 List of appearances
- ^ YouTube: SDCC 2011: Halo Universe Panel Part 4
- ^ Halo: Primordium pages 356-357
- ^ Amazon.com: Halo: Primordium product description
- ^ a b c Halo: Primordium, Chapter 2
- ^ a b Halo: Cryptum, page 23
- ^ Halo: Cryptum, page 60
- ^ a b Halo: Cryptum, page 130
- ^ a b Halo: Primordium, Chapter 1
- ^ Halo: Primordium, page 350-357
- ^ Eleventh Hour reports, part 4
- ^ Halo: Primordium, page 378-379