Poisoned Blades

Source: Codex: Dark Eldar (2002), p. 14

The Dark Eldar frequently make use of poison-coated blades. However, they have to be used with great care in case the Dark Eldar end up poisoning themselves! Hits inflicted in close combat with poisoned blades always wound on a 2+, regardless of the victim's Toughness. However, this ability may not be combined with the ability of any other weapon in close combat (eg, it can't be combined with a power weapon's ability to negate saves, a plasma grenade's ability to negate cover, or an additional close combat weapon's +1 Attack, etc.)