That is defame an online nom-de-guerre who you have no idea who they really are.
By defame, I mean can you be charged with a criminal or civil offense of defamation?
For a simple example, were I to say that Cecil wears army boots in bed for sexual gratification, would he (in his current regeneration) have grounds for legal action (I assume the allegation is possibly untrue, or at least he will claim it is)
Not in that example, no. It’s obviously a joke. Hustler Magazine v. Falwell - Wikipedia
A flame war between pseudonyms who are unknown in their real identities is unlikely to result in a civil defamation suit. Criminal defamation does not exist in the US.
However, anyone with the filing fee and a willing lawyer can file a defamation suit. It is very difficult to prevail in a defamation suit taken all the way to trial, but it can be done. It would really depend on what was said about whom, whether they were a “public figure” and a whole bunch of other things.
“Obviously a Joke” ! Are you sure?
As a general rule, defamation requires: (1) a false statement (2) that is communicated to a third person, (3) fault*, and (4) harm to the subject of the statement.
Assuming, for a moment, that we don’t know who the real Cecil is**, that person can’t claim that he’s been harmed. However, Cecil is also a brand name associated with retail products, and there is a separate tort called “commercial disparagement” which is basically defamation relating to a business, product or service.
*The level of fault required varies with the type of plaintiff.
**Just pretend, okay?
For one thing, it would be very likely that the defendant would be able to argue that their statement was an ‘opinion based on disclosed facts’ - the disclosed facts in this case being the plaintiff’s posting history. Such opinions are not, legally speaking, defamation. Cecil, as an entity that exists only as the author of public articles, consists pretty much entirely of ‘disclosed facts’.
Only in the Pit.