Eradicate Chaos? Hah! One might as well try to exterminate one’s own shadow.
Do not presume to enforce a simpleton’s philosophy upon the Emperor’s Inquisition.
Bury your head if you must, but mine eyes are open yet.

– Excerpt from the sixth trial of Inquisitor Lichtenstein

Xanthism is one of the oldest philosophies of the Inquisition, named after Inquisitor-Master Zaranchek Xanthus who was executed as a heretic in the early 32nd millennium. Xanthus was accused of Chaos worship, and although he professed his innocence strongly, he was eventually burnt by a team of fellow Inquisitors. Throughout, Xanthus had maintained that he remained pure, though he admitted that he did on occasion utilize the forces of the Warp and Chaos to achieve his goals. It was his firm stance that such power could be harnessed without the spiritual corruption of the wielder that was to be later picked up on by other Inquisitors. It is the ultimate goal of the Xanthites to harness the power of Chaos for Mankind. They believe that Chaos cannot be defeated, for it is merely a reflection of humanity itself. However, those energies and powers created by its existence can be turned back for the benefit of humanity, rather than being an enemy. This does not mean that they advocate giving in to Chaos, but rather to capture the essence of Chaos and turn it to useful rather than destructive purposes. In the same way as the Warp (and so Chaos) allows Warp travel, Astrotelepathy, and psykers to work on Mankind’s behalf, so too can other facets of Chaos be controlled, tamed to the Emperor’s Will by the Xanthites.
Xanthites investigate all aspects of the Warp and Chaos, investing its power into themselves where possible, destroying it only when necessary. They will use Chaos-tainted artifacts, daemon-weapons, books of Chaos lore, and other heretical items, utilizing the powers and abilities of these weapons and tools to combat the incursions of Chaos, heretics, and aliens.