There are a lot of new agents coming into Delta Green and many of them have questions about where they came from, what they did, and how they got to where they are. Luckily, there has been an ongoing conversation on r/DeltaGreenRPG about just that. The thread can be found here, and we encourage you to look because it has plenty of insights, but we’re posting here the general outline created by user ProfDoctor404 to help get new agents started.
Here is an abbreviated rundown of the history of Delta Green from the original core book. Many of these things are subject to change with the new edition.
1917: The Office of Naval Intelligence, or ONI, creates the P4 Division (Parapsychology, Paranormal, and Psychic Phenomena), otherwise known as P Division to look into reports of the paranormal during WWI.
1928: Project COVENANT: The Raid on Innsmouth. The Treasury Department (The Secret Service), the Dept. of the Navy (ONI, U.S. Marine Corps, U.S. Coast Guard), and the Bureau of Investigation (the predecessor of the FBI) raid Innsmouth, recovering extensive evidence of Deep Ones and a bit about the Mythos at large. Survivors eventually folded into the P Division.
1928-1941: P Division raids and destroys numerous Deep One Colonies throughout the globe, as well as gathers numerous Mythos tomes and artifacts.
Dec 1941: The United States enters WWII after the Japanese Attack on Pearl Harbor, P Division also joins, merging with the Office of Strategic Services (OSS). The group becomes unofficially known as Delta Green, after the green triangles that mark DG files.
1942-1945: Delta Green does battle with the SS Karotechia, Nazi Germany’s Occult Mythos organization, ultimately defeating it in the summer of 45. Delta Green and the OSS are disbanded in Oct. 1945.
1947: The Roswell Incident. A UFO crashes in Roswell, NM. Truman orders the creation of the Majestic-12 Special Studies Program to study the remains. Former DG members successfully lobby for the reinstatement of Delta Green as an independent organization.
1948-1956: Delta Green runs Operation SOUTHERN HOSPITALITY to track down and eliminate surviving Karotechia members in South America and beyond, hitting it’s high point with a raid on a Karotechia base in Antarctica in 1952. Also during this period, DG comes into a Cold War conflict with the Soviet NKVD/KGB.
1955: Project COVENANT and P Division files, tomes, and artifacts as destroyed by an insane DG researcher, Daniel Freis.
1963: After the sinking of the USS Thresher of the coast of Cape Cod, Delta Green runs Operation RIPTIDE, which finally destroys the Deep One city of Y’ha-nthlei off of the former town of Innsmouth, which had been only partially damaged in 1928.
1950s-1969: Delta Green runs Cold War operations throughout the world, including major operations in Africa and Southeast Asia.
Nov 1969: A mishandled Delta Green Operation into Cambodia during the Vietnam war fails disastrously, leading to the deaths of over 300 American Servicemen, forcing the Nixon administration to launch the invasion of Cambodia in order to cover it up. The Joint Chiefs of Staff launch an investigation to fix blame and deny knowledge of the incident.
Jul 24, 1970: A disgraced Delta Green is officially disbanded and begins life as an illegal conspiracy. Thus begins the ‘Cowboy Years.’ This era is marked by very, very loose organization within the conspiracy, with members mostly acting on their own accord.
Dec 1970: The new conspiracy launches its first operation, diverting B-52 bombers from communist targets in Cambodia, Laos, and Vietnam to bomb Tcho-Tcho villages and religious sites.
1971-1993: Between 50 to 80 Delta Green operations occur during this period. The operations are mostly ad hoc and little exists in the form of records.
1993: DG investigation in Texas leads to the widely publicized destruction of the Branch Davidian’s cult in Waco, Texas.
Feb 25, 1994: Longtime Delta Green member Major General Reginald Fairfield, US Army (Ret), successfully transmits his files on pre-1970 DG operations to other DG members before his assassination in his home by agents of NRO DELTA, the wetworks branch of Majestic-12. MJ-12 is still operating with official approval of the US Govt, though it has long been infiltrated and influenced by the Greys, a servitor race created by the Mi-go to manipulate human governments.
Spring/Summer 1994: Professor Joseph Camp of Delta Green persuades surviving Delta Green veterans to reorganize the group so that intelligence can be gathered and centralized, particularly to counter the increasing threat of MJ-12.
1994-2001: The years of the organized Delta Green conspiracy. DG does battle with MJ-12 and many others. New members are recruited into the conspiracy as old veterans fall.
Sept 11 2001: Terrorist attacks on the US.
Late 2001 to 2002: Major overhaul of US intelligence community. MJ-12, which has been slowly losing contact with the Greys, is disgraced and disbanded. Members of the Delta Green conspiracy are ‘brought in from the cold’ and pardoned and folded in with the remaining elements of MJ-12 that haven’t left for the private sector or were eliminated by DG. Delta Green is then re-legitimized by the US Govt, and exists as a uneasy partnership of former enemies, fanatically and fatally devoted ex-conspiracy members, and jaded yet ignorant and shortsighted new Govt bureaucrats.
This last entry has been gathered from available information about the new version of the game and is not concrete until the release of the core rulebook. If you can get a hold of a copy, the original Delta Green rulebook contains an exhaustive history of the organization and it’s many enemies.
Good luck new agents, you’ll mostly be alone out there.