There is no term "academical" in real world vocabulary. The word you may have meant is "academia", which refers to 'univerities, schools, studies, books, libraries, students and professors' and such. "Academic" refers to things that are relative to "academia" ... this has been corrected. Please use Category: Academic to describe only articles which are of an academic nature, ie papers published or articles with long lists of citations.
Articles in Category:Wiki are a bit special. Those are links to wikis on wikia.com dedicated to a MUD. I only wrote a short text for some of them to count as an article (short articles are not added to the counter.) I think that External Links is a misleading because it's on the same website.
It's impossible due to the 'idiot-proof' category features here to remove categories through normal editing techniques, even when viewing source. Perhaps you could discover how to do this; I put in a query and let's see what happens. I took a look at TrekMUX and this is an example of one that needs revisiting due to miscategorization.
In the Edit window, you cannot see the categories in the text, but they can be edited in a window to the right, under Add features and media. When you hover your mouse over the category, an icon to remove the categories appears. It looks like a pot, for whatever reason.