Schola Progenium
The Schola Progenium are schools for orphans run by the Ecclesiarchy in Warhammer 40,000. Its various students come from all walks of life, and regardless of what they were before entering, they come out as dangerous, Emperor-loving killing machines. In the Schola Progenium, a child is trained daily in how to read Ecclesiarchial scripture, hold and shoot .75-caliber automatic weapons, identify dangerous and heretical individuals, and how to sip tea.
Progena of each Schola are ideal members of just about every branch of the Imperium. They make good clerks, (need to be able to hold a bolter when some punk comes in with a knife) adepts, (only a man who loves the Emperor dearly can bear with writing for a 38-hour workday) and especially good Arbitrators, for obvious reasons. They often become Commissars or Storm Troopers in the Imperial Guard, and female graduates usually join the Adepta Sororitas. Usually.