[Yvelina]

I think that Miasma C'tis is the strongest of the 'nasty' themes. Maybe the only theme that can really stand its ground against the astral/air powerhouses.

The two Dead Ermor themes can be devastating against the AI, but in MP, things are stacked against them. The Ashen Empire is decent, and with it, diplomacy is an option. Pangea Carrion Wood... not too many good players have looked hard enough at that theme.

Now, note that I do not include Abysia among the 'evil' themes. Enslaving the humans and keeping them down does not make them anymore evil than the Vanir, Jotun, etc...