The Shadow Proclamation was an organization responsible for keeping order in the Milky Way Galaxy. It had several prisons within the galaxy, including Impel Down. Its operatives included Blackout (before he stopped working undercover), Artrix (before she died), and Sunstorm (before he left to join Blackout). It was commanded by the Shadow Architect until Blackout dismantled it.
Following the collapse of the Shadow Proclamation, its duties in the Milky Way Galaxy were assumed by the Galactic Government.