A very enigmatic aspect about the Greys that not a lot of people talk about, is that according to researchers such as Barry Fitzgerald the Greys have a very acute aversion to iron, which is something that apparently they share with other paranormal entities such as Earth Spirits, the Djinn and some of the old Gods from world mythologies, which suggests there might be a link between these different groups (Missing time, 6:12).
To give you an idea of the amount of different Grey species that have been reported we have: the short Greys who are 3.5 to 5 feet tall and who are mostly used as working robots by the Greys themselves and by other ET species. The tall Greys who are 6 to 8.5 feet tall, come in shades that vary from pale white to gray and have huge human-like eyes underneath their membrane lenses, and the taller Greys standing at 9 to 12 feet tall and having elongated heads with small pure black eyes. Their frame resembles more that of a human, the men are naturally muscular, they have darker grey skin tones and their facial skin is wrinkled (Campobosso, 157). We also have the Greys that belong to the higher classes in their society, who come in colors such as Green, bronze and a type of violet-purple tint.
Then we have the well known EBENs from Zeta Reticuli, who shared a common ancestor with the Greys a longtime ago and who have recently ended their war with the main Grey masterline. In fact, there seem to be many grey races from the Reticulum constellation. We have the Orons from Orion constellation who stand between 6 and 7 feet, are predominantly female and female-run, they have bulging eyes, a dark pigmentation with more rounded heads, long limbs with extra joints and slender fingers (Campobosso, 163). We have the Zeta humans from the Cetus constellation, who can also come in shades of blue and golden. 
Of the many notable Grey hybrid races we have the Grey insectoids, reportedly from Mu Draconis, a binary star in the Draco Constellation. They are a hybrid of the Tall Greys and Mantis beings standing at a staggering 8 to 10 feet tall. We also have the so-called “Sassani” beings, who allegedly are a half human/half grey hybrid among a variety of other combinations and who come from a parallel reality 300 years in the future. Lastly we have many kinds of grey-reptilian hybrids like the Zeta Lizard Humans from the Bootes Constellation.
Now, we are going to take a look at the alleged origins of the Greys’ abduction and hybridization programs on planet Earth. According to Len Kasten’s book “Alien World Order”, on or about February 21st, 1954 US President Dwight D. Eisenhower met with a contingent of the ET group we refer to as the “Greys”. Out of that alleged meeting came an agreement between the government and the Greys that some refer to as the “Treaty of Greada”, that would allow them to abduct a limited number of humans of their choosing and to examine them in order to study the physiology and psychology of the human race, provided that they gave a list of those who had been abducted (Kasten, 342). In exchange for that, they would provide the military with advanced technology, especially in the fields of biotechnology and anti gravitational propulsion systems. Supposedly, this treaty was necessary because Galactic Law does not allow alien races to abduct members of a native planetary population without an invitation to do so. 
Following this alleged “Treaty of Greada” in 1954, the door was opened to what eventually became a widespread phenomenon around the world, as the human abductions ultimately led to the multiple hybridization programs that we hear a lot about nowadays. Furthermore, since the Greys arrived at the meeting in spaceships we assumed that they came from off planet, but according to author Len Kasten, they actually came from an underground realm here on Earth that has existed for millenia, which is supposedly inhabited by the Greys as well as other ET groups such as the Draco Reptilians and a certain group of Sirians.
The first abduction that took place in this new era was the famous case of Betty and Barney Hill, who on September 19th, 1961 were taken out of their car on a deserted road near Indian Head, New Hampshire, and up into a craft where they were subjected to physical examinations by the Greys. Among other things, Betty Hill was shown a star map that many researchers believe to be referring to the Zeta Reticuli system. This case is so well known that the site where this happened has been commemorated by a roadside historical marker. Their famous abduction story also entered into mainstream recognition as it was adapted into the 1966 best selling book “The interrupted journey” and the 1975 film “The UFO Incident”.
Many researchers like Len Kasten point out that ironically, the treaty that allowed for abductions like the Betty and Barney Hill case was not really necessary, since we had already been given an anti-gravitational disk to back engineer as a gift by our friends the EBENs, which allegedly landed in Kingman, Arizona on May 21st, 1953 but thanks to the extreme compartmentalization of top secret information regarding the ET phenomena, that event may only have been known at that time by members of the Majestic 12 and not the president who sign the treaty, which highlights some of the many challenges that we  to face as this policy of secrecy and denial are still going on.
A more modern understanding of the complex abduction and hybridization phenomena highlights that there seems to be soul contracts involved in the process, which may also be tied up to events in present, past or even future lives. The topic gets even more controversial as we discuss the alleged existence of implants, which are physical objects placed in someone’s body after they have been abducted, which are also claimed to give some people enhanced psychic abilities. Whatever the case may be, we need to be very respectful to the testimonies of abductees, which have been thoroughly studied by researchers like John Mack, the former head of psychiatry at Harvard’s Medical School.
To conclude, we can say that even though the Greys are a very challenging group to understand from a human perspective, we need to remember that understanding their mission and their influence on our planet is essential for the Disclosure process currently going on and for our own spiritual development, since both Greys and humans are ultimately part of the divine Creation that lives within us. See you next time!