Years ago, the Voltron Force ultimately defeated Prince Lotor, resulting in h...
Voltron: The Third Dimension
Season 1 Episode 12: Dark Heart
Haggar seeks to avenge the break up of her relationship with King Alfor. She imprisons Alfor's spirit in a Crystal Robeast, which soon does battle with the Voltron Force. But if they destroy the robeast, they will also destroy Alfor's spirit.