House Col'Khak, known also as the Suzerain House of Col'Khak or The Col'Khak Collective, is an alliance of Imperial Knight Households that were founded in the latter 30th Millennium during the Great Crusade on the frigid Agri-World of Atar-Planitia in support of the then recently implanted Forge World of Atar-Median. As such, the Collective owes its fealty first to the Mechanicum -- through its bonded Forge World of Atar-Median -- and second to the Imperium.