Crimos were a type of specialist soldier used by the Federation. "Crimo" is stated by Blake to be a portmanteau of "criminal psychopath". They were used to assist Travis in his gambit in the Communications Tower on Exbar, in place of his usual crew of Mutoids, who were unavailable to him as a fugitive. It is therefore possible that Crimos were really mercenaries, unable to be enlist in the standard Federation military because of their unstable tendencies. (B: Hostage)
Personality
Crimos displayed a far greater enjoyment of violence than most other Federation soldiers. When Vila asked "why should they want to kill us?", Blake simply replied "because they enjoy it". One Crimo stated that the enjoyment of inflicting pain was the mark of a true Crimo. On Exbar, their leader under Travis, Molok, appeared particularly amused by any instance of pain or fear in his captives. He proudly told Cally of his "high Intelligence Quotient" when she identified him as a Crimo, implying they were considered to be of poor intelligence. (B: Hostage)
Equipment
On Exbar, Crimos were seen clad in black armour, bulkier than the standard Federation uniforms, with black skullcaps. The Crimos seen on Exbar had armour trims in colours of red, yellow, green and orange, likely signifying different ranks. Green, the colour worn by Molok, was meant to be the most senior in this scheme, and yellow being the most common.
Crimos also displayed skill in using unconventional weaponry, which included the use of bear traps and nets to capture the crew of the Liberator, archaic devices rarely seen in the hands of Federation soldiers. On Exbar, only Molok was seen to use a firearm in combat, though a lower-ranking Crimo did take Vila prisoner using Vila's own weapon. (B: Hostage)