The Diagu were a collective of humans who resided on the planet Targyon. During the time of the Great Jedi Purge, they showed support for the Jedi Order. Sometime between 14 BBY and 9 BBY, The Grand Inquisitor journeyed to the Diagu as he had received information that the Jedi Knight known as Tensu Run was creating a safe haven on Targyon. The Diagu would not disclose the whereabouts of the Jedi to the forces of the Galactic Empire, resulting in The Grand Inquisitor killing their elder. He then gave the order for the remaining humans to be put to death, and their children were to be taken to the Imperial capital, Coruscant.
The Diagu made their debut appearance in the first issue of the Star Wars: Inquisitors comic series from 2024. This comic, released on July 3, 2024, was brought to life by Marvel Comics, with writing by Rodney Barnes and illustrations by Ramon Rosanas.