Advanced Research Group United Support, also known as the A.R.G.U.S., is a research group and special ops division of the U.S. government, charged with the task of taking down terrorist threats in secrecy and without public knowledge. However they are willing to let vigilantes such as Green Arrow and the Flash operate in their respective cities without interference, as their work does have significant benefit.
Under the leadership of the immoral Amanda Waller, the organization became very corrupt if not excessive in its methods, as they became no better than the very threats they are supposed to protect the U.S.A from, committing unspeakable acts with no regard for human life, this includes the extortion of whomever is convenient to their benefits, usually threatening their family members if they don't comply, they also used felons for Task Force X to carry out life-threatening operations in exchange for working off their sentencing, they were even willing to order a drone to destroy Starling City in order to stop Slade Wilson's army from leaving. When meta-humans started emerging, A.R.G.U.S. even began to study them in order to weaponize their powers.
Following the death of Amanda, Lyla Michaels becomes the new director of A.R.G.U.S., reforming the organization, as everything they do is now based on morals, principles and the value of human life, as they are no longer using criminals or unwilling individuals for their benefit, it also seeks to rehabilitate criminals instead of weaponize them. However, at the same time, Lyla's new position of authority also has forced her into various difficult situations, sometimes making decisions that would more closely follow Amanda's protocol, such as holding dangerous terrorists in prison without trials or stealing secrets and technology from even allies.
A.R.G.U.S. was formed by a group of officials in the U.S. government to deal with major threats like the League of Assassins, H.I.V.E. or the Church of Blood.
A.R.G.U.S has been using the same flanking patterns for years, so much so that Oliver was able to identify A.R.G.U.S agents simply by their behavior, observed during his past experiences with them.
Oliver Queen has occasionally interfered in A.R.G.U.S. business and does not trust their intentions; due to his bad experiences with the organization in the past.
After the death of Amanda Waller, Lyla Michaels was made the new head of A.R.G.U.S., she looked into "cleaning" all of Amanda's past mistakes.
The main A.R.G.U.S. building was then secured with new security cards, access codes and retinal scanners, as well as advanced meta-human power dampeners; however, it does not affect all meta-human powers, such as Barry Allen, who has become immune such tech; due to him spending six months inside the Speed Force.