"I will never be a memory."

In Final Fantasy VII, Sephiroth is the biological son of Professor Hojo and Lucrecia Crescent, created as the result of an experiment by the megacorparation Shinra, where he was injected with cells from the extraterrestial lifeform known as Jenova while he was still a fetus. Upon discovering that this same process was also responsible for the creation of the world's monsters, as well as mistakenly believing that Jenova is his bioligical mother, Sephiroth decides to follow what he believes to be his destiny as Jenova's heir by becoming a god and destroying the planet. Seven years prior to the events of Final Fantasy VII, Cloud was able to successfully stop Sephiroth by throwing him into a Mako reactor along with Jenova's severed head. Although he is officially listed as killed in action, Sephiroth's body lies in a comatose state at the Northern Crater, where he uses his newly acquired ability to directly control Jenova's cells to cause them all to gather at the Northern Crater, as well as causing Jenova's headless body stored at Shinra's headquarters to shapeshift into Sephiroth's image and likeness to act as his new vessel until his plan could be completed.