In our previous article, we looked at invisible beings — dragons and unicorns — who some might think of as animals.1 In earlier articles, we explored invisible astral beings and invisible human races.2,3 In this article, we look at four more groups of invisible or subtle beings who fulfill essential roles and functions within Earth’s system. Each of these four groups has so many different aspects that a book could be written on each of them though our knowledge is still very limited. Here, we describe their essential elements so that we can understand their roles in Earth’s system.