Codex: Chaos Daemons (2013), p28 — The Eternal Rivalry

There exists a hierarchy of sorts within the ranks of the Ruinous Powers, though it ebbs and flows according to the vagaries of the Great Game. Currently, Khorne is held as the mightiest of all, for the practice of murder and blood sacrifice stretches to the dark beginnings of the universe. Though Khorne sees the use of sorcery as the refuge of cowards, his closest rival, Tzeentch, thrives on the raw stuff of Chaos and is hence counted second in influence. Where Tzeentch would see hopes thrive and fortunes change, the Father of Plagues works towards the defiance born of stagnation, despair and hopelessness. In times of galactic pandemic, Nurgle's power can eclipse even that of his brothers in darkness. Last in the pantheon is Slaanesh, whose earthly luxuries and sensual lusts defy Khorne's desire for indiscriminate slaughter. Yet the Dark Prince knows well how to play on the obsessions of his rivals. Khorne's single-minded bloodlust, Nurgle's quest to infect every living thing, and Tzeentch's compulsion to dabble in the fates of mortals - all are obsessions which the Lord of Excess can turn to his will with a whispered promise.