The Omega Department is an American Intelligence organization.
This ultra, ultra-secret department is said by its current Director to be "the most powerful organization in the country, actually in the world". It has been around about as long as several of the more well-known 'alphabet' agencies, it just has made sure that keeping its existence a secret has been one of its top priorities.
Again according to its Director, "the Omega Department has been around for quite a few years. It was started back in the early cold war days as a safety valve for the continuation of our government if something should happen. They threw money at this program like you wouldn't believe. Problem is, the program morphed itself over the years, and is now so big and strong it has become scary. Make no mistake. Its main purpose is still the protection of our country, its people, and its secrets, but it has now expanded to our allies as well. I think the fact that someone like you, who spent twenty five years working around it, yet you never had an inkling it existed. I think that speaks volumes for our programs security". Additionally, "the Omega Department, became so secret, not even the president of the United States knows about it. This is a case of need to know or better yet, plausible deniability."
The Director doing the explaining is William Bolton, the 'you' is the Director's brother, Austin.
The Bolton brothers are twins with Austin being the older by four minutes. They come from a family of quite wealthy parents though they were hardly well off in the early years.
The elder Austin had joined the military after college and went on to become part of the elite Green Berets. When we meet him he has reached the rank of Colonel.
The junior William went into politics right out of university and quickly worked his way to the Senate where he soon became chairman of the ultra-powerful Appropriations Committee. It was then that he was approached to be part of Omega in order to become its latest Director.
When it became known to William that Omega had a traitor in its ranks, he brought Austin in to help root him out. Having been made aware of the organization, Austin sticks around to become second-in-command.
Oh, in the first adventure we learn that back when the twins were very young, their still poor parents had a second set of twin boys, Ronald and James, which they were forced by financial reasons into giving up for adoption. They play a big part in that first story but then fade into memory.