I was relistening to The Blanched Soldier and realised how much Colonel Emsworth in this makes me think of Augustus Moran
"Freddie.. - for whatever reason- was very unwell. Probably my doing let’s be honest. Always such a.. delicate little boy and I- just.. built this- no I forced this hardened shell around him. This scaffold- to use a term you’re familiar with Mr. Dodds- that perhaps obstructed. And blocked out the real boy inside. And of course because of all that -he had a very challenging.. mental health.. prognosis. And I will swear to any Doctor, even now- nothing fixes a man’s mental health more than the presence of other men. And structure. And the Marines, later the Army was just the ticket. But he was.. mislead.. and he took- to.. Well he would get involved with many things, eventually even heroin."
Sebastian Moran quite probably has a similar history, it's just presumably instead of drugs he turned to crime.