Irony of a situation refers to an event where the action that made by a certain character actually resulted in the opposite effect of what the character's intended to be. Writers usually use irony of situation to move the plot forward or as a comedic value.
4 is... They trained from the moment they walked to age 20 when they joined the army. They were let out around age 55. They were taken away around age 6 and given no food or water and were punished if theynwere cought stealing.