Should remember they are creating killers from children. You want them to be rational and sane killers, not psychopaths. Brainwashi-I mean, nurturing them to be assassians that dont buckle under the pressure of their very real emotions and the varoius real traumatic experiences, such as almost dying or needing to kill a loved one, is more than necessary and calls for a character role that could supplement enormous character development. Mental and emotional character devolpement. 

This is the potiential of a counselor.
Though you could definetely have a character that can endure, comprehend, and weather any physical and emotional battering, but it is more realistic that most teenagers and young adults are not that stable or emotionally strong.