Last Order: Final Fantasy 7

In the events of Last Order, taking five years before the beginning of Final Fantasy VII itself, Sephiroth was ordered to inspect the Mako Reactor outside the town of Nibelheim with a small entourage, consisting of one other member of SOLDIER and a few Shin-Ra MPs. Among this group was SOLDIER 1st Class member Zack and his buddy, a 16-year-old Shin-Ra trooper named Cloud Strife. Nibelheim was Cloud's childhood home, but he avoided showing his face and revealing himself to his childhood friend Tifa Lockhart out of shame over not becoming a full-fledged member of SOLDIER as he had sworn to do several years earlier. At the reactor, Sephiroth found several pod-like chambers containing monstrous creatures, apparently former humans, possibly mutated by injection with Jenova cells and exposure to Mako. Deeper inside, he found a larger chamber labeled "JENOVA," which contained a very strange feminine-looking creature. Deeply disturbed by the fact that the creature had the same name as his "mother" and by the idea that he himself might have been created in an experiment similar to the one that created the monsters in the pods, Sephiroth made his way to the mansion that had been occupied by Shin-Ra researchers and began reading the research notes that were located in the basement library. As a result of what he learned, Sephiroth was enraged and psychotic. Based on the Shin-Ra reports, he came to believe that Jenova was a Cetra, and therefore that he himself, Jenova's "son," was the last survivor of the Cetra. He also believed that the human race had betrayed the Cetra 2,000 years earlier, leaving them alone to defend the Planet from a calamity it had faced (eventually revealed to have been Jenova itself), and resolved to take vengeance for his "ancestors." He burned Nibelheim to the ground, killing nearly everyone within the village, including Cloud's mother, and then returned to the Mako Reactor in the Nibelheim Mountains. He was pursued by some surviving villagers, including Tifa and her father. Cloud and Zack, as of yet unharmed, also followed. When Tifa arrived at the reactor, she found her father dead with Sephiroth's sword left beside his body. In anger, she took the sword and charged Sephiroth in the pod room, although he took his blade back from her and cut her down, nearly killing her. A moment later, Zack arrived and rushed up the stairs in the pod room to Jenova's chamber, attempting to stop Sephiroth. Zack was sent reeling out of the doorway of the chamber and onto a pod. Sephiroth attempted to take Jenova with him, but before he could do this, Cloud charged into the room, carrying Zack's large Buster Sword, and taking Sephiroth by surprise stabbed him through his abdomen with it. Believing Sephiroth was finished, Cloud went to tend to Tifa. Tifa was eventually saved by her martial arts master, Zangan while the remaining survivors of the Nibelheim incident were used as experiment to create a Sephiroth clone by a ShinRa professor called Hojo. 5 years after being experimented on, Zack and Cloud escape from Hojo's clutches to the town of Midgar. While on their way, Zack is shot and Cloud left to die in his Mako poisoned state. Cloud makes his way to Midgar to be found by Tifa which marks the start of Final Fantasy VII.