Unless otherwise noted in the army list, all Harlequin units and characters benefit from the following special rules.

Holo suit - Rather than physical armour designed to absorb shots and blows, Harlequins rely on a sophisticated holo-suit to misdirect the enemy. In game terms this means that Harlequins have no armour save as such, but always count as if they were in cover with a 4+ save. They get no additional benefit if they really are in cover and weapons which normally ignore cover will ignore their special save. This also applies in close combat and so they always gain the benefits of a defended obstacle unless assaulted by an enemy with grenades which negate cover. As it is a cover save the Harlequins receive no normal armour save in close combat. A holo-suit save cannot be used against an attack that uses a template or blast markers (such as a battle cannon or flamer) nor can it be used to save a model if it is being transported in a vehicle that is destroyed. Models fighting a Harlequin in close combat can become confused and disorientated by the evershifting colours and patterns of a holo-suit. Any model fighting a Harlequin in an assault halves their Weapon Skill (rounding up).

Flip Belts - Flip belts are compact anti-grav devices which generate a short range negative-gravity field which, when combined with the Harlequins already prodigous acrobatic abilities, allows the Harlequins to make all manner of gravity-defying leaps and bounds. Harlequins can ignore difficult terrain - treat difficult terrain as open ground for the purposes of movement. When advancing after winning an assault, or Harlequins can move 3D6 inches instead of 2D6 inches (note that they fall back 2D6 inches as normal). In addition, a Harlequin model may use their full number of Attacks and any specialist close combat weapons they have when within 2" of an enemy in an assault - this is instead of the 1 Attack with no special rules that other models have in this situation. Remember though that models which assault the enemy must try to get into base contact if possible.

Mask of Fear - A Harlequin's mask incorpates a holographic generator that projects images of monstrous faces and demonic visages, intensified by a short-range psychic field which increases their opponent's sensitivity to fear and despair. Any enemy unit fighting in an assault against a Harlequin reduces their Leadership by -1.

Fleet of Foot - Instead of shooting in the shooting phase, a Harlequin unit may run instead. The unit moves D6", which is not modified by difficult terrain.

Dispersed Formation - Harlequins fight almost as individuals, and rely less upon the coherency of their unit to defeat the enemy. A Harlequin model must stay within 4" of another model in the unit, rather 2" as is normally the case. See page 43 of the Warhammer 40,000 book for details of unit coherency.