In Eumenides, the human race is divided into two groups, caryatids and cynosures. Cynosures are the "main characters", the people whom the Executors dote on in the story of history. The caryatids are everyone else. The game material leaves it up to the GM to decide how "real" the caryatids are, varying from them being totally normal people who just don't happen to have the attention of the daemon sultans, all the way to them being superficial imitations of people that are only "real" enough to fool the cynosures who meet them.
Visually, we came down on the far end of the spectrum of reality, with the non-cynosure components of reality as merely 2-d cutouts, able to fool the cynosures only with the magic of the Executors. This was just a matter of wanting to make a consistent choice as to how it was going to look, and to choose a really distinctive visual style that sets the game apart.
The arcane runes on the cynosure are the mark of the Executors. The nimbus is perceptible to all Initiates, and notifies the onlooker of the cynosure's protected status. Any supernatural influence on a cynosure is certain to draw the Eyes of the Executor, and shortly thereafter, a beefy response team of armed daemons as the All-Lords protect or avenge their beloved puppet.