No problem Thayan. In Star Wars d20, the Dark Magics are best expressed in The Dark Side Sourcebook. In this, Dark Magics are mainly used through Dark force Skills, Like Force Lightning, Force Drain, and Feats like Force Storm and Sith Sorcery. The best PrC for this is undoutably The Force Witch, adopting powerful aspects of the Dark Magics.
In essence, the Triplets come from a Primitive Planet, Dantooine to start. Secondly, Force Talent in a time like The Galactic Civil War was highly misunderstood, and in primitive cultures like Dantooine and Dathomir, perceived to be not the Force, but rather the power of deceased spirits and ghosts. Dark Magics, actually the Dark Side of the Force, are what these are.