Complex sentence: In two episodes, Jade encounters a future version of herself: a young woman who is the head of Section 13 (Captain Black having left to set up "Section 14"), and came back in time once to stop Drago.
Split into simpler sentences: In two episodes, Jade encounters a future version of herself. This future Jade is the head of Section 13 (Captain Black having left to set up "Section 14"), and came back in time once to stop Drago.