Koriel Zeth

Koriel Zeth was a Martian magos who governed Magma City and allied with Loyalist factions during the Mechanicum’s civil war. A priest of Mars, she established an independent forge inside a volcano to pursue scientific inquiry beyond the restrictions enforced by Fabricator-General Kelbor-Hal. Her principal project was an Akashic reader, a device designed to access universal knowledge directly.

When Kelbor-Hal aligned Mars with Horus and initiated a religious coup, the Taghmata—the military forces of the Mechanicum—stormed Magma City. The stronghold fell to the assault, but Zeth refused to yield her technology to the Fabricator-General. She died alongside her machinery as volcanic lava engulfed the facility, while her circle of associates, including Dalia Cythera, survived to preserve her legacy.

Zeth’s career illustrates the tendency of Mars to utilise capable innovators before ultimately expending them. Within the history of the Horus Heresy, her defiance demonstrates that the Mechanicum’s civil war was not an administrative disagreement, but an uncompromising ideological conflict decided by the armed destruction of dissenting forge cities.