Search terms used: Child soldier + psychology/mentality, military psychology, soldier mentality, military experimentation, psychology/military tags in this community.
I have a character who has no memories before the age of... let's say six or seven. He woke up in a military facility, probably with at least a year or two of training (which might fall under "instinct") but no memories of family/friends/life outside the facility. It's possible that he's a test tube baby but it's... unclear.
In this facility he makes one "good friend" and is semi-friendly with some others around his age. However, something that goes on in this facility causes him severe mental trauma, enough to split off into a separate personality that does what he feels he cannot.
He eventually escapes, at the age of something like 10 or 12, though the separate personality ends up killing those he escapes with.
There are a few questions here.
1) At such a young age, what would military training be like?
2) What sort of experiments would be likely to break this character? The scientists are setting out to make superior soldiers, so they wouldn't be out to deliberately break their subjects.
3) After escaping, how strongly would the "soldier mentality" stick? If it matters, he joined a peacekeeping organization that intervenes (sometimes violently) in armed conflict, with the aim of eradicating war.
Thanks for the help!