Been a few including everyone mentioned on here but i would have to say Kenwright for about 28 years of achieving absolutely nothing while continually boasting about how good he thought he and his board were. He turned one of the most successful, respected and feared top flight clubs in the country into a club that won nothing under his stewardship, deserved no respect, continually gets mocked and shamed and is expected to be in a relegation battle before a season even commences.
Even mid table is a pipe dream for Kenwrights Everton but mustn't forget the 'good times' and must be grateful. Newer generation Evertonian's weren't even born when we were last formidable and have been manipulated by Kenwrights stewardship to believe that mid table is good when it is absolutely cack. Pre Kenwright Everton, the aim was the top and to be the best and anything less wasn't good enough.
Would be hard to beat that for a villain.