The Arbiter

Thel 'Vadam, later known as the Arbiter, was born into the ruling Vadam family on Sanghelios, a powerful lineage presiding over the State of Vadam. From an early age, he was trained in the martial traditions of the Sangheili, guided by his relative Lak 'Vadamee. As a young warrior, Thel demonstrated exceptional skill and resolve, earning the right to join the Covenant military where he adopted the "-ee" suffix, becoming Thel 'Vadamee. His early service included campaigns such as the Covenant assault on Madrigal in 2528, where his prowess in battle quickly earned him distinction.

Through continued acts of valor, Thel rose to the rank of Shipmaster and achieved the title of Kaidon within his keep, a mark of both military authority and political leadership. During his time as Shipmaster, he suffered an injury during a training session—an incident kept hidden by his family due to the Sangheili cultural association between medical treatment and dishonor. While recovering, Thel crafted a traditional doarmir-fur cloak by hand, which he wore thereafter as a reminder of his vulnerability and the cost of complacency.

Between 2535 and 2552, Thel’s strategic brilliance and combat leadership led to his promotion as Supreme Commander of the Fleet of Particular Justice. Under his command, Covenant forces were responsible for the deaths of over a billion humans, the loss of at least seven colonies, the destruction of more than 123 UNSC vessels, and the deaths of over 23,000 personnel. One of his most decisive actions was his leadership during the Fall of Reach, where he orchestrated the Covenant’s overwhelming assault and ordered the pursuit of the fleeing UNSC vessel, the Pillar of Autumn, which ultimately led his fleet to Installation 04.

Once at Halo, Thel commanded the Seeker of Truth and coordinated Covenant efforts around the ringworld. However, when the Flood was unleashed, the situation rapidly devolved. Though he ordered an evacuation of the installation, the infection spread quickly, even claiming a Prophet—the Minister of Etiology. Amid the chaos, the ring was destroyed, and the human vessel Ascendant Justice was captured by the Master Chief. These failures led to Thel being recalled to High Charity and brought before the High Council to answer for the catastrophe.

Stripped of his rank, Thel was sentenced to death, but the Hierarchs Truth and Mercy offered him a chance at redemption. They named him Arbiter, a title once reserved for ancient, venerated warriors, but now repurposed as a mantle for holy suicide missions. Though accepting it meant a likely death, Thel agreed, seeking to redeem his honor and ensure the legacy of his bloodline.

As Arbiter, Thel carried out missions for the Covenant until he was betrayed by the Prophets and the Jiralhanae. Realizing the depth of the Covenant’s lies, he allied with humanity and fought alongside the Master Chief and UNSC forces to stop the activation of the Halo rings. After the defeat of Tartarus on Delta Halo, Thel renounced his ties to the Covenant, changing his name from 'Vadamee to 'Vadam, a symbolic gesture that resonated across Sangheili society. Many of his people followed suit, seceding from the Covenant and initiating the Great Schism.

Haunted by the past yet committed to a new path, Thel became a unifying figure among the Sangheili, working with humanity to prevent the annihilation of all sentient life. While he, like most Sangheili, was once zealous and steeped in rigid tradition, his experiences as Arbiter deeply changed his worldview. He became more open-minded, pragmatic, and accepting of former enemies, even going so far as to embrace human alliances and technologies.

Appearance: Towering over most humans, he possesses the imposing physique typical of a Sangheili—tall, broad-shouldered, and powerfully built, with digitigrade legs and clawed, three-fingered hands. His skin is a muted grayish tone, textured with reptilian-like scales, and his mandibles—four in total—frame a mouth filled with sharp teeth.

He wears an ornate and battle-worn suit of ceremonial Arbiter armor, forged from dark, burnished metal with silvery-blue highlights and intricate etchings across the chest and pauldrons. It layered with reinforced plating that protects vital areas while allowing freedom of movement in combat. The chestpiece is adorned with a prominent, curved crest design, and one shoulder is capped with an angular, upward-jutting guard. Subtle energy conduits and lattice-like paneling line his limbs.

Like the standard Sangheili combat harness, the Arbiter's armor is equipped with an energy shield. It also possesses active camouflage capabilities, but this feature can only be enabled for a limited time. Thel's primary weapons are an Energy Sword and the Vostu-pattern Carbine. The Vostu-pattern carbine served as one of the Covenant's primary medium to long-range weapons.

The Great Schism, also known as the Covenant Schism, was a major civil war between the forces loyal to the Covenant (led by the San'Shyuum and the Jiralhanae) against the Covenant separatists (the Sangheili and their followers.

Originally an ancient Sangheili order, the Swords of Sanghelios was reinstated in the aftermath of the Great Schism by the latest Arbiter and the organization's leader, Thel 'Vadam.

The Sangheili, or "Elites" as they are known by humans, served as the military leaders of the Covenant. The Sangheili are the only race within the Covenant permitted to build and command starships within the Covenant, though the crews are always composed of a mix of races. The Jiralhanae, or "Brutes" as they are known by humans, were the most recent addition to the Covenant, and served as soldiers and bodyguards within the Covenant military. The Lekgolo are a race of worm-like creatures that can combine to form large, intelligent assemblages called Mgalekgolo, known by humans as "Hunters". Clad in nearly impenetrable armor and armed with their trademark Assault Cannon, they served as the Covenant's heaviest ground troops. Hailing from Balaho, the Unggoy, or "Grunts" as they are known by humans, were the most common and low-ranking caste of the Covenant. They breathe methane gas, and thus must wear a large tank on their back full of methane to survive on other planets. The Kig-Yar, or "Jackals" or "Skirmishers" as they are known by humans, were the scouts and marksmen of the Covenant military due to their superior senses. San'Shyuum, also known as Prophets by many individuals, are a near-extinct sapient species native to Janjur Qom. Prior to the Great Schism in 2552, the San'Shyuum served as the leadership caste of the Covenant. By that time, the San'Shyuum had exerted complete control over the Covenant's religious and political affairs.

The Human-Covenant War was instigated by the High Prophets of the Covenant following a discovery which led them to believe that humans were directly related to the Forerunners, contradicting their ancient religion. Seeking to keep various political and religious orders intact, the High Prophets declared a holy war of genocide against the human species, and the discovery of their relation to the Forerunners was kept a secret. With superior firepower, numbers and technology, the Covenant would repeatedly overpower the UNSC across hundreds of human-inhabited worlds, including the heavily defended strongholds of Reach and Earth. Humanity would win only scattered and costly victories.