Master Builder

The Master Builder, also referred to as Faber, was a notable Forerunner individual most famed as the architect of the Halo Array. He was the head of the Builders, a rate associated with technology and engineering, and among the most powerful Forerunners. The Master Builder was a noted political opponent of the Didact, who argued against the Halos as a crime against the Forerunners' Mantle to safeguard life. In order to make his Halo strategy palatable to the Forerunner leadership, the Master Builder worked with the Librarian to implement the Conservation Measure on the facilities of the Array so that galactic biodiversity could be restored in the event of the rings' activation. Despite his rivalry with the Didact, the Master Builder would later assist him in creating the AI Mendicant Bias.

The Master Builder's ultimate fate is unclear, though some records suggest he may have been killed in the final days of the Diluvial War.

In the Covenant religion
Though the Covenant had access to few concrete details about the Master Builder, his role as the creator of the Halos was known mainly from the Kandonom Codex. Due to the monumental significance of the "Sacred Rings", he is likely the most popular deity in the classical Covenant pantheon. A literal translation of his title in the Covenant common language is Etanna'hron, though he is often known by numerous epithets depending on context and tradition, including Marruk, literally Faber or Smith, or Yrandesh, meaning Ring-maker, and Aram'aramin, or Forge-Lord. In Covenant iconographic tradition, the Master Builder's cynosure or devotion-image is a sleek cuboid form fashioned with intricate angles, bearing a ring or "Unbroken Circle" upon it; the colors silver and purple are associated with him.

Among the Covenant faithful, the Master Builder is frequently associated with applied sciences, craftsmen, techaries and discovery-priests, artisans, architects and builders. Even with the fall of the Covenant, his worship-cults remain popular among practitioners of these trades, though worship of the Sacred Rings themselves is less common.