Mutiny on Junica
The first known action of the Edification Corps took place some time after the tragedy at Numenar Point and the disappearance of the Fourth Sphere Expansion fleet.
During the difficult campaign against Chaos forces on Junica, T'au Commander O'Ryn refused Aun'Va's orders -- maybe because the fact that the deceased Ethereal Supreme had been secretly preserved as a solid-light hologram might have been revealed by a tank shell impact that slew his retinue. In doing so she became the first T'au since Commander Farsight himself to disobey a command from an Ethereal.
Several solar days later, an Edification Corps fleet descended upon Junica with the intention of detaining O'Ryn's entire command, only to find that the Commander and her loyal warriors had fled to the Farsight Enclaves. All witnesses to O'Ryn's act of treason were sequestered, and the remaining cadres on Junica broken up and dispersed across the empire.
Fifth Sphere Expansion
Terran years later, when the Fifth Sphere Expansion found the survivors of the Fourth at the other end of the Startide Nexus, vessels from the Edification Corps were a common sight around the Fourth Sphere Gate in Nem'yar Atoll, as the T'au political officers cross-examined the survivors of the ill-fated expedition.
Recruitment of the Charpactin
The Edification Corps is known to have drafted many Charpactin, whose strobing bursts of ultraviolet colour have proven surprisingly effective at subduing and transfixing living beings, rendering them docile and amenable.
- Codex: T'au Empire (8th Edition), pp. 24, 39