Jenova is a key element character from the video game series, Final Fantasy, specifically featured from the video game installment, Final Fantasy VII. An alien life-form and the Big Bad of the game, as it causes the beginning of many other antagonists, including Sephiroth as well, Jenova also appears in the Prequel of Disney vs. Non-Disney Villains War.
Disney Vs Non-Disney Villains War
Pre-War: Calamity Unleashed
Prior to the events of the war, Jenova is summoned by Sephiroth, on purpose to end Ansem's goals, from opening his world's "keyhole", and spread it's darkness over the world. Both Jenova and Sephiroth destroy what it is left of Ansem's world, before they depart to parts unknown.