Dante is the main antagonist of the first anime adaptation.

She is the former lover of Hohenheim, and has used Philosopher's Stones to transfer her soul to new bodies for around four hundred years. She leads the homunculi, either creating them herself, or finding them after they are created, and uses them to create conflicts in the hope of having a desperate alchemist create a new stone for her. She first appears as an elderly woman, who is the former alchemy teacher of Izumi Curtis.

(Source: Wikipedia)