You don't have to believe in Eristic Avatars to be a Discordian, but it helps.
Eristic Avatars are sent down into Reality, the original Rorschach, for the
purpose of keeping things from becoming so well ordered that they stop
working. This they often accomplish by insisting that certain arbitrary
interpretations of reality are the only valid ones. That causes Strife which
results in Confusion which revitalizes Holy Chaos. Most Eristic Avatars display
certain signs by which they can be certified, such as employment as civil
servants. So far, the most successful Eristic Avatar has been Confucius.
Eristic Avatars can also be ascertained by the fact that they are always
ignorant of their mission and have no idea they are serving Eris or, for that
matter, that they are even promoting confusion.
That is made possible by the
Law of Eristic Escalation,
of which you must be innocent to serve as Eristic Avatar. (For an unknown
reason, it does not work as well for those of us who are guilty of it.)