Visitations are occurring between literally hundreds of alien groups and human contactees. Some of these alien groups are on Earth only briefly, for perhaps only one contact with one individual, and this either out of curiosity or due to a very specific mission. Other alien groups, like ourselves, have been around for eons, and have an intense interest in the future of Earth, our future home. The Sirians, Pleiadeans, and Nordics, among other commonly reported Service-to-Others groups, are not so intensely interested as we, but are here primarily out of a sense of service. Their missions are as numerous as they themselves, as opportunity abounds. Like ourselves, they must wait for The Call from a human, and then depending upon the situation, the goals of the human, and the requested guidance from the visitor, they jointly may be of service to the Earth and its many inhabitants.
The hand of the various groups can sometimes be seen in the type of endeavor undertaken by the human who gave The Call. For instance, Pleiadeans are intent on educating humans in the pleasant nature of 4th Density Service-to-Others existence, the sense of community and potential for being playful and having fun. The Sirians are more war like, have this history in their past, and take The Call from humans who could use logistical advice during confrontations. Nordics are very scientific and intellectual, and dislike the spotlight. They thus work behind the scenes, and their contactees are never heard of.