A Harlequin, known in the Aeldari Lexicon as a Rillietann, is a member
of a very distinct sub-group of the Aeldari species who belongs to none
of the existing Aeldari factions, including the Craftworld Asuryani, the
Exodites or the Drukhari. They are the keepers of the Black Library and
serve the enigmatic Aeldari deity called the Laughing God.
The Harlequins see no distinction between art and war, and their
outlook can best be explained by reference to the legend of the Fall;
one of their self-appointed duties is to keep this legend alive through
their performances. The central figure of Harlequin belief is Cegorach,
the Great Harlequin -- also known as the Laughing God.