Is there another name for ennead?

title, epithet

A fictitious name is called a pseudonym or pen name, for authors. Also: alias, nom de plume, assumed name, stage name. For the best results for your use, the built-in thesaurus in your word...

From the Related Link: "first name, Christian name, forename, given name, surname, family name, middle name, maiden name, pet name, nickname, last name, handle, moniker."

Cathos is the German spelling of the Spanish name Catos.

Another name for screen name is 'nickname' or 'user name'. The use of the term "logon" might also apply.