ELBOW (or Elbow) is the name of an organization in the world of Kill the Past. They are mentioned by name only a small handful of times in The Silver Case and Flower, Sun, and Rain. Morichika Nakategawa explains that there are no factions, only Elbow, which controls all factions. Edo Macalister describes them as "the brainwashing facility of an advanced nation", while the FSR ending text describes them as The Summit of Advanced Nations and "comprised of secret organizations from across the world", suggesting a near-global influence. They are backers of organizations responsible for conspiracies such as the Shelter Kids Policy and the training at Coburn Elementary School (see the killer7 section below). More directly, they were the masterminds of the Silver Eye production plan on Lospass Island. It is implied that the staff of the Flower, Sun, and Rain worked under them without knowing their real machinations, and Edo in particular was a high level administrator. When Edo found out more about them, he betrayed them and tried to destroy the island, calling in Sumio Mondo.
Remy Fawzil and Yoshimitsu Koshimizu refer to a plan of theirs as "Euro Maspro", suggesting a continuation of the mass productions of the Shelter Kids Policy. The ending text mentions that ELBOW creates a "Next Maspro" using Tokio Morishima's hyena, but no further details are given. After this, ELBOW ceased operation.
In the original Japanese version of killer7, there are a few differences regarding the data Holbert gathered on Emir Parkreiner. One of these is Emir's social security code, which in the international versions is "EAGLE", but in the Japanese version is "ELBOW". This parallels the theme of Japanese politics' involvement in American politics being hidden from the Americans, as the westerners playing the game see their country's bird instead of the truth. This seems to suggest that Coburn Elementary School, and/or Emir in particular, had a connection to ELBOW, which may hint towards Edo Macalister's involvement at the Union Hotel and his knowledge of Garcian. It is likely, given the similarities between the two, that Coburn's child training is based on the same technology and methods as the training in the Shelter.
Another possibility for ELBOW's involvement in killer7 is the International Ethics Committee, which operates around the globe and calls its agents "Hyenas".