I was having a similar discussion with a couple of people the other day over the use of villan or villain, I asked John Lerwill (Official club historian)what his thoughts were and this is what he told me-
In respect of “Villan” and “villain”. The first (“Villan”) is a made-up word meant as a proper noun to describe a person who is an Aston Villa supporter. The second term (“villain”) is a standard English word that refers to a rogue or suchlike. The two words are quite different, and only the first should be legitimately used to refer to a Villa supporter. The fact that some people use the word “villain” when they mean “Villan” is a spelling mistake on their part. Therefore it is not reasonable to suggest that the two words are inter-changeable. They are not.