Mine are Shapeshifters. Their strengths/powers depend on what class they are:
A basic (or common) shapeshifter can assume the form of a human, a mammal, and a bird and can perform simple magic (they can cloak themselves from humans but not other shapeshifters, they can do simple healing spells on themselves and others). Common class shapeshifters can use the enhanced abilities of their animal forms (such as the excellent vision of an eagle, the sense of smell of a dog, the strength of a bear) only while in animal form. For example, a shapeshifter that can change into a bear must be in bear form to use the bear's strength.
Royal class can assume the form of a human, a bird, and a couple of mammals (usually two or three). They can cloak themselves from humans and common-class shapeshifters but not from other royalty. They have advanced healing skills and can magically compel common shapeshifters to do their bidding, but they cannot do this too often as their powers diminish with use (they need to rest). They can use their animal senses while in any form.
The rarest and most powerful class, the Dunamis, can take the form of an unlimited number of birds and animals (must be a mammal, reptile, or amphibian - no fish or invertebrates). He can also take on hybrid forms, such as a humanoid with wings or a centaur. He can cloak from anybody, has highly advanced healing skills, and will know your name and whether you are lying to him - sort of a very basic type of mind reading. Daecon has been shown to bring the very recently deceased back to life, and can visit the afterlife (Astral Plain). He can transfer some of his advanced magic into a common shapeshifter to "upgrade" their class, and can also remove powers to "demote" them. He can remove all of a shapeshifter's powers - not quite turning that person into a human because they are biologically different, but making him no more powerful than one. My MC, Daecon, is a Dunamis.
The thing that makes them most different, though, is that they are all male. They reproduce sexually and all carry two Y chromosomes. Technically they are hermaphrodites as they have both male (external) and female (internal) reproductive bits. As the story currently stands they can produce a fertilized egg but that egg must be implanted into a surrogate human female to develop into a baby. This is a plot point, and the reason for this necessity will be shown later.
