The Red Emperor first appeared in White Bear & Red Moon as:
The Red Emperor was the latest of a long line of wizard-kings, answerable only to their mother, the goddess of the Red Moon. They were immortal, in that no “natural” death could take them, though they could be slain by physical or magical combat. Because they were a fanatical and warlike dynasty, many Moonsons descended to earth to rule. Each appeared identical and maintained the Imperial policies of his predecessor, so that it seemed one man ruled for centuries. The Red Emperor is both a Hero and a Magician.
I still think this is a workable description of the Red Emperor. There are many mysteries around the various people who have held this title – for example, we know nothing official about any of them prior to their ascension (although rumor abounds and sometimes we get hint and pieces). Most people assume the Red Emperor has always been the same figure.
I don’t think that each Red Emperor truly appears identical – rather their iconography and public depictions remain constant. The Red Emperor is a figure surrounded by ceremony and ritual. Perhaps his build, facial features, hair color and style all varies, but he is always recognizable as the Red Emperor. Like Jesus in Byzantine art, the Red Emperor is an icon more than a person.
And of course, this is what makes him hard to really get a handle on. There is a person there, but unlike Argrath or Harrek, it is very hard to discern them. We even refer to him with either his title or by a mask with no past or identity beyond being the current mask of the Red Emperor. The title is the real person, not its current holder (which is both fascinating, and very much in the manner of the ancient world).
There are rumors that Moonson is little more than a figurehead, a walking icon that is the locus of Lunar worship, but actually all decisions and deeds are done by others. Other rumors suggest that each Moonson is an ambitious and remarkable figure capable of beating off rivals to gain and hold on the title. As with Argrath and Harrek, there is room for plenty of interpretations.
Near Eastern · Sassanian, 4th century A.D.