The defining characteristic that sets wikidemons apart is the fact that their ego drives their interest in the pages they infest, rather than an actual concern for scolarly pursuits.
Like most generic demons, they liken themselves unto gods above the mere mortals that dare enter their self-proclaimed domain.
This does not mean they have any special or insightful knowledge of the page, but that they merely demand that all other beings must be inferior in their understanding of the posessed pages, as the wikidemon's ego can allow no peers to their self-imagined wisdom.
The wikidemons can be most easily spotted by their domination of article history as perpetually reverting any changes that dare go against their self-worshipped decision of what the page should be, and by their complete domination of an article's talk page, often to the point of responding not only to multiple other people who question their ultimate control of the page, but hapless passers by and even themselves.
There are, at this time, no known ways to truly combat, vanquish, slay, banish, or otherwise exorcise wikidemons from their adopted domains.
Until such a method is devised, wikis will forever remain unreliable sources, as any given wikidemon manifestation completely destroys the legitimacy of the page and entire wiki it infests.
Wikidemon: WHO DARES DISTURB MY SLUMBER? Someone removed my reference to satan inventing icecream? I shall revert this fool's change, and then write 11 paragraphs on the talk page explaining why he's a moron for doubting my logic. It will look nice next to my other 300 paragraphs. I should put it as a reply to myself, since he didn't post to the talk page about why he removed it!
Bob: Why does this page claim satan invented ice cream? I'll remove that reference.
Wikidemon: WHO DARES DISTURB MY SLUMBER?...