The Last Chancers
Amongst the Imperial Guard, Unique regiments consisting of convicted criminals of all stripes and shades who have avoided execution or a grim future in the form of a servitor, only to be pressed into penal legions alongside thousands of others for a chance to absolve themselves of their crimes though suicidal acts beyond those of normal guardsmen. Either though serving their sentence or being cleared of charges posthumously, A penal legion almost guarantees the innocence of an individual if they refrain from fleeing, but a messy, gribbly end awaits those who flee from battle or try to escape confines during transit, normally administered by an explosive collar or a bolt pistol.
Yet again, amongst the many thousands of penal legions reside the thirteenth penal legion, while not being the thirteenth legion to be formed, they are however legendary amongst the guard for being a virtual death sentence, even other penal legions see those residing in the thirteenth as lost causes. This dread reputation a direct result of Colonel Schaeffer being the most heinous and downright evil imperial guard officer to ever exist. There is a high chance men under his command will die before reaching the frontlines, normally a direct result of forced marching along the quickest path en route to the frontline, normally footslogging though "hazardous" environments, luckily death = an easy pardon, so it's not all bad.
The Last Chancer series follows legionary Lieutenant Kage as he shoots, stabs, strangles and shouts his way through a brutal sentence serving under Colonel Schaeffer in the Last Chancers as he leads the thirteenth penal legion on suicidal missions across the galaxy. Consisting of three major novels, 13th Legion-Kill Team - Annihilation Squad and a scattering of short stories, Deliverance - Liberty.
History
13th Legion
We start by being behind the eyes of a man who is not Kage, entering a lab and finding the "experiment" he was overseeing has, at some point in the past, wandered off, at which point he comes to the conclusion