Looking for a story where a boy lives on a planet he gose to a doctor to upgrade his inplants

Looking for a story where a boy lives on a planet he gose to a doctor to upgrade his inplants then go on a mission then gets traped in a building or a vault where the enemy looking for him or something else. There is thing in the place that changes him. The former boy get ssomething
special to fight his enemy .There is two empires fighting each other.