Kalran: Tales of the four nations/Penance center

"To destroy a tree. You must purge both the roots, and it's seeds."

-The first edict of the Ouroboros first chief of police, Ordoza

To those suspected conspiring against the Ouroboros government and arrested their lives, and those of their family, are forfeited, for the governess edict sees no use in redeeming criminals and must purge the tree to prevent future crimes. But, to ensure obedience, they lie to these criminals that they will be freed once they done their duties.

Once sent to the prison the lucky ones are executed. The rest are turned into the penitent legion. Where the prisoners' are placed in large vats of specialized panacea, where they briefly die from the overdose, before the devil magic revives them again, making them biologically dead and never needing to eat or drink to survive, or feel anything. After this their skin and organs are removed, grafted, and integrated into armored diving suits to become one functional unit. Ending with the prisoner now getting a lobotomy, erasing everything but their crime, to ensure obedience. This process is a one-way street, and a fate worst than death.

Through magic and Devil blood splicing, the people inside the heavy suits were given enhanced strength and durability. Their suit exoskeletons contained the life support machinery and magic needed to keep them alive during their duties, allowing the penitent legion to lift heavy loads and do other strenuous tasks, as well as resist the cold and pressure of the deep ocean. Serving the government as penitence for their past crimes.

And ever they serve the government for the hope of release. But in reality its a great lie, for the governess edict never forgives, especially since the government lied to them that they can undo the procedure that turned them into these soldiers. And for years, thanks to the process making them immortal, they may fight for that pipe dream, having their mind routinely examined so that they keep believing on that hope that their release will be in a few more years. And so they forever serve the government, for the hope of freedom, until they finally die, and be freed, in battle.

Also due to their lobotomy and being undead all penitent soldiers will never retreat even when their morale breaks, but the effects of fighting with a broken morale is even worse. And EMP/MDP pulse will not only stun them but severely damage them. But so long as their not blown apart they can be revived by the Collectors.