CaptainRedbeard
Most of the Last Chancers were once loyal servants to the emperor, some were rouge mercenaries caught in their sinister acts, all are criminals sent to the penal legions to serve out their punishment for crimes committed to the Imperium of Mankind.
Schaeffer would hand-pick his rag-tag regiment's troops from Imperial prisons' worst convicts because of some natural talent they displayed or because they possessed an uncanny instinct for survival so that they could serve as part of an elite ad hoc military team intended to achieve some difficult, usually borderline insane military objective of the Imperium.
The convicts are given a "last chance" by Schaeffer to be forgiven of their crimes in the eyes of the Emperor of Mankind and this is achieved by receiving an Imperial pardon from the Colonel. These pardons are awarded only to those members of the regiment who survive a number of military operations determined by Schaeffer. Those that die during missions are also awarded a pardon for their service and sacrifice.