M41) - Led by a conclave of Shadowseers, the Midnight Sorrow aid Inquisitor Sophia Vilimas in defeating the Alpha Legion on Safehaven. Here, the masque's Skyweavers swoop and soar, shedding very real blood as they engage in ritual dances and duels with the best challengers the Wych Cults have to offer. They wander the Webway and occasionally appear at Aeldari settlements: on a Craftworld, on Commorragh, an Exodite Maiden World, or even, rarely, a human world in the Imperium of Man. Indeed, so deep is their connection to the Laughing God that it is rumoured the Webway itself flexes and shifts at this masque's behest.

While most Harlequin masques are willing to ignore the animosity between their divergent kin, the Winter Sun have not performed for, or fought with, the Drukhari for many Terran millennia.

Their acrobatic and deceptive skills, as well as their unique weapons and equipment, render them such mystifying and terrifying enemies that some of the less-developed races of the galaxy have incorporated them into their mythology as magical spirits or eldritch monsters. Each Harlequin knows these saedaths on such an intricate level they are able to enact these strategies with flawless precision. Since the Fall of the Eldar, a crystal tome bounded with chains of light has rested upon an obsidian plinth at the heart of the Black Library.

The Harlequins are both servants of the Laughing God - the only deity of their race to survive the mighty Fall - and custodians of the hallowed Black Library of Chaos. The day of the Aeldari has come and passed, and the Midnight Sorrow strike now, before the long night begins.Acting quickly they sought aid from their brethren to save the Maiden World and serve as mediators between the Craftworld Saim-Hann and the Drukhari of Commorragh. Death Jesters send volleys of fire to cut down key targets, always with an eye for what cruel humour they can find in the kill.