Echo is considered an idiosyncratic squad due to the fact it's filed under the category Fireteam. There are only three squads that are within the Fireteam group: Charlie, Echo, and Quebec. Charlie is reserved for the youngest group of children (save from pre-school aged ones), usually from the ages 7 through 11. Echo is for children around the ages of 11 through 15, where Quebec is for the remaining between 15 through 18.
Like Charlie and Quebec, Echo serves as a squad for stronger and more ruthless and rebellious children, whom usually require a higher level of supervision. The known members of Echo are Alex, Niko, Elijah, Morgan, and Fordyce. It is unknown who the supervisor of Echo is, but it is assumed to be an Onyx Guard of some sort.
Like the normal categorized platoons, the three Fireteams are located in barracks aligned by one another, but are however under more security.