What interesting ways are key people picked and trained/taught in your world?
Be it for a classic mentor and apprentice tradition like knights and squires following noble traditions or wizard and apprentice following more meritocratic ways. Or is it like more like mass compulsory education with talent being singled out for further advancement or is it cuthroat backstabbing conscription with only the strongest being worthy of advancement.
For example in my Infinite Horizon universe, an interstellar sci-fi setting, on the the military side of things there is the "Fleet", the "Armada" and then there is the Lighthouse keepers a more techno-scientific insitution.
First the Lighthouse keepers are critical in maintaining and expanding humanity FTL station. To do that they need the best and brightest, so they have teachers in most schools keeping an eye out for gifted children to recruit into their own advance Lighthouse school, parents and the child can refuse but it is considered a great honor. However getting into Lighthouse school is not the end all be all as kids can dropout or be rejected as the program gets more challenging. Dropping out or failing out of Lighthouse school is not considered shameful or dishonorable (it is a hard and gruelling program) however there is occasional discrimination between the gradutes and dropouts and even between dropouts ("you suck you dropped out 5 years in, I made it to 9 years before being failed out"). Although not a hard tradition sometimes Lighthouse teachers become mentors to the kids they pick out following their progress and careers lending help when needed.
The Fleet is your classic Lawful Good space defense force mirroring our modern western militaries with recruiting only volunteer adults and letting people choose their roles within the fleet after they prove their proficiency and have the appropriate qualifications with a scattering of private contractors amongst them. Unsurprising the Fleet is called the shield of humanity.
The Armada on the other hand was created as the sword of humanity, in secret, in response to the Auriga crisis (tldr oh shit we're not alone, aliens exist, we lost a colony to a dead alien civilzation anything can be out there). The Armada can be described as Chaotic Goodish with them recuiting specific people secretly as needed and an entire planet Laconia (iykyk) as a breeding, training and recuitment grounds for the rest of their personnel.
The mandate of Laconia is to bring out the best(or worst) of humanity to neutralise threats to humanity (in contrast to the Fleet who is tasked to defend humanity). This mandate encompasses genetic enigineering, bioengineering augumentations and most interestingly of all from birth conditioning and brainwashing.
The problem is or rather the policy is that it is better maintain a diversity of upbringings lest there is key weakness in a monolithic program and there is strength and adaptability in variety. Add to that the uncertainity on what kind of upbringing/training works, Laconia is effectively an unethical exprimental psychologist wet dream.
So in the different corners of Laconia there individual kids being raised by ultra loving parents that they want to protect, to kids being raised by unloving parents that they desparately yearn approval of, to groups of kids raised to be in cutthroat competition with each other or groups of kids being abused so much they have to work together and rely on each other to overcome the adversity and so on so forth all arcoss the planet. These kids are not only being trained to be military personnel for the Armada but also be to scientists, engineers, spies and politcal leaders that infiltrate into common society.
Some of my stories have been about these characters with these backgrounds coming together and interacting with each other with all sorts of shenanigans and drama. For example
-The unloved daughter, trained and engineered to be a harden supersoldier discovering her loved sister, an aspiring influencer, who grew off Laconia >!the plot twist is the Laconia program is not restricted to the planet and them meeting up was part of the expriment!<
-A Brotherhood of abused boys rescued/escaped from Laconia on path of vengenance for the small colony who welcome them in and hid and shielded them against conscription. >!meanwhile unknown to them (being in a backwater sector) a civil war is being waged between anti alien and pro alien factions of the Fleet!<
-A classic buddy cop duo of a low self esteem Lighthouse dropout and a gung ho Fleet officer running around trying to solve problems and making messy mistakes(and learning from them). >!meanwhile they are being used as proxies by the Lighthouse keepers (via the dropouts Lighthouse mentor and guidance by a secret AI cult) to shutdown and disrupt scientific and technical research that the Lighthouse prefers to keep a monoploy on!<