The alien life form we refer to as the gods of Mount Olympus, who are resident on the giant comet, the 12 Planet, are not unique as 3rd Density visitors to Earth. They were allowed to visit Earth, in the past, even though they too were in 3rd Density and on the same level as the inhabitants of Earth. Are they the only group in 3rd Density that has so visited Earth? There have been several, but these visits are very rare, and with this one exception have always been benign. An example of a 3rd Density visitation is what is known in the US as the Pascagoula episode, where an alien with rigid legs floated to communicate with an ex-combat veteran. This veteran responded to a request, in essence gave The Call in response to a call, for this meeting with a 3rd Density entity that had evolved from a form of intelligent tree to occur. During its evolution and previous incarnations, this entity, not being able to maneuver, had never been in combat. They wished to learn, vicariously, what combat was like. This entity traveled to Earth as the guest of 4th Density entities.
What made the alien life form we refer to as the gods of Mount Olympus unique, is that they had achieved space travel on their own. This achievement is beyond what Earthlings now enjoy, as even though the trip was within your Solar System, a shuttle between Earth and the 12th Planet during one or another of the periodic swings past the Sun, nevertheless the trip required the aliens to go into hibernation for some years. It was this ability, in concert with their space flight technologies, that allowed them to make the trip at all. Consequently, as this was a feat they could repeat, they dug in, as the saying goes, and made themselves at home on Earth. This became disruptive of Earth's free will progress, and was stopped. These aliens are, however, elsewhere in your Solar System, proceeding with their mining operations, which are similar to the ones they conducted on Earth.