Codename
An agent's Codename in the Skull brotherhood is a sign of his/her identity or means of identification. Every agent Codename is meant to be unique and no two agents are meant to have the same Codename obviously to prevent confusion.
The Codename is usually given at adulthood or when a member has proven himself or herself in a trial or mission. in special circumstances, a code name can be given to a person who has displayed a certain trait or skill such as Quiet.
A Codename is usually a description of a person or comes about due to a person's unique trait or character.
For instance, Quiet is quiet.
Pain is in charge of bringing pain being the Master of Torture (M. O. T) and her martial arts is geared towards causing the maximum amount of pain.