Diabolus

Oh, yes it does! However that does not mean that fact applies to ALL contexts; I understand that it's likely I missed the point of your post, however, within my interpretation of what you said it seemed like you insinuated that Sval made a rookie error. Maleficent within the context used IS still a valid word to use, even if an esoteric and eccentric one.

The word Maleficent is a bit old-fashioned and you don't hear it often. Maleficent means something very close to malevolent or diabolical and is a lot stronger than naughty or mischievous. It's odd seeing it used in such a context, but I think it is still grammatically correct. Someone who is malevolent is described as malicious in their actions. When you say "My actions were malevolent", that is still correct. So, I think him saying "My actions were maleficent" is correct as well.

Have you seen their alliance page?

Satan is your friend.