Commissars - see Codex: Imperial Guard
Special Rule
Oops, Sorry Sir: Deathworld Veterans resent strangers telling them what to do or threatening their friends so Commissars have a very difficult time maintaining control. They also suffer a disproportionally high number of 'accidents' when serving with Deathworld troops. Roll a D6 for each Commissar before setting them up (roll for models in reserve when they deploy onto the table). On a roll of 1, the Commissar has met with an unfortunate accident and cannot be used.