Ligeia and Lady Rowena
When it comes to foils, you couldn't ask for a better pair: Ligeia is black-haired, dark-eyed, and strong-willed; Rowena is light-haired, blue-eyed, and weak. The narrator loves Ligeia and hates Rowena (ouch). They represents opposite sides of the wifely coin, the yin and the yang. By including Rowena, Poe not only provides a vessel for Ligeia's resurrection, but makes Ligeia seem all the more potent.