Republic Commando's: Echo squad; Book one: Echo Is set during the Clone Wars. It tells the story of clone trooper CT-21-0408 after being presumed dead during the escape from The Citadel. It is written by Embo2000 (P.T), and is the first novel from him, as well as the first novel in the series Republic Commando's: Echo Squad. The story explains how Echo gets off the citadel, and culminates to him creating and supervising an experimental group of republic commandos made up of Captain Rex, Commander Fox, Trooper Boil, and Sergeant Sinker.