6. Edea (FFVIII)
When she makes her debut, little is known to us about Edea, save that she is the Sorceress. It's immediately obvious that Garden is withholding some crucial information about her when they assign Squall and his companions to kill her, and if you want to pick holes in the plotline, seriously questionable that Garden would send only three rookie SeeDs, an instructor, a resistance member and one untested sharpshooter to take her out. Plot holes aside, Edea's tyranny and presence are immediately obvious as she makes her entrance by murdering Galbadia'a President in front of a crowd of thousands as a night of celebration quickly escalates into sheer panic and terror. Edea is one of the villains that works best by being shrouded in mystery and by being a character with very little dialogue. Her seduction of Seifer both mentally and sexually (we assume) pitches her as a master manipulator capable of turning petty rivals into serious threats, and ends up pitching the nations of Balamb and Galbadia into war. What's unquestionably the biggest flaw in Final Fantasy VIII, though, is the revelation that Edea is actually being possessed by another sorceress from the future. (Wait, what?) The real tragedy of this plot miscalculation is that it undoes so much of the emotional journey the charcaters take when they realise they were all orphans and that Edea was their Matron. Coming to terms with the fact that they now face the woman who raised them as an enemy was one of the most powerful moments in the game, but most of that was taken away upon learning Edea wasn't in control of herself, and that the villain is actually some shoehorned plot device from a different time. If only Square had stuck to their guns and kept Edea as the villain all the way throughout the game, keeping her the matriarchal figure to a bunch of orphans who saw her as a mother, Edea might very well be at the top of this list.