A plague censer is a Warpstone Weapon and counts as a flail with the following additional rules.

At the beginning of any round of close combat in which a unit equipped with plague censers is in combat, all models (friend or foe) in base contact with one or more Censer Bearers, Plague Chanters, or Plague Priests that have a plague censer, must take a Toughness test or suffer a single wound with no armour save allowed. This means that a model need only take a single such Toughness test in each round of combat, regardless of the number of plague censers that it might be adjacent to. All such wounds count for combat resolution, Wounds caused by this rule are resolved before Impact Hits, issuing challenges and revealing Assassins.

All Clan Pestilens models (Plague Monks, Plague Priests, Plague Censer Bearers, Plague Furnaces, Lord Skrolk and Plagueclaw Catapults) suffer a wound only on a roll of 6.