Nibelheim Incident

The Nibelheim Incident is a pivotal event in the Final Fantasy VII where Sephiroth, acclaimed hero of SOLDIER, descends into madness and destroys the village of Nibelheim. The hometown of two of the game's central protagonists, Cloud Strife and Tifa Lockhart, Nibelheim's destruction marks the beginning of Sephiroth's villainy after he learns of his "true" origins. The incident is frequently depicted in the Compilation of Final Fantasy VII, and has been subject to numerous retcons, although the basic chain of events has mostly remained the same.

Story
Following a report of a problematic increase in the monster population around the Mt. Nibel Mako Reactor, Zack Fair and Sephiroth, accompanied by a small contingent of Shinra troops which included Cloud Strife, arrived at the town to investigate. The following day after their arrival, Tifa Lockhart is hired as a guide to show them up the mountain, however, during the expedition, the breaking of a rope bridge sends the group falling into a gorge. While Zack, Sephiroth and Tifa are more or less unharmed, only one of the Shinra troops survives; Cloud Strife.

At the reactor, Zack and Sephiroth enter while Tifa remains outside with the trooper, unbeknownst to her that he was Cloud. Inside the reactor, the two SOLDIERs discover a series of tanks containing vaguely-humanoid creatures submerged in Mako, with the chamber at the top of the stairs labelled "Jenova" - the name Sephiroth was told belonged to his mother. As the pair approach the chamber, Genesis Rhapsodos appears and informs Sephiroth about what Jenova was and about the Jenova Project's two branches, Project S and Project G. Genesis tells Sephiroth he is the ultimate monster created by Project S, as Angeal Hewley was the ultimate monster of Project G. Much like the humanoid creatures locked in the tanks behind them. Leaving the reactor and returning to Nibelheim, Sephiroth finds a secret basement in the town’s abandoned Shinra Mansion containing a vast library of Shinra research journals and submerses himself in reading them; which included reading about Professor Gast Faremis and Professor Hojo’s false identification of the creature Jenova as a Cetra. Sephiroth spends three days in the basement alone reading Shinra's research on Jenova and the culmination of that research, the Jenova Project.

Emerging from the library believing that he was the last Cetra and the creature Jenova’s son, Sephiroth also came to the conclusion that the humans had betrayed the Cetra to extinction, having abandoned them to a mysterious disaster. Sephiroth leaves the mansion and sets the town of Nibelheim ablaze. As the town razes to the ground, having been someplace else, Tifa arrives and finds her instructor, Zangan, who tells her it was Sephiroth who burned the town and that her father went to the Mako Reactor to confront him. A wounded villager warns her that is where Sephiroth has gone, but Tifa rushes to the mountain regardless. Zack and Cloud arrive shortly after, having stayed in the town’s Inn and been busy saving the town villagers, and Zangan tells them Tifa has gone to find her father and Sephiroth. While Cloud stays to help Zangan rescue the townspeople, Zack follows after Tifa to the reactor. On the mountain outside the reactor Tifa finds her father grievously wounded by Sephiroth, after he dies in her arms pleading for her to flee Tifa takes Sephiroth's Masamune and declares her hatred of Shinra and SOLDIER before charging into the reactor, attacking Sephiroth as he approaches the door of Jenova's chamber. However, he easily takes back his weapon and cuts her down, sending her falling back down the stairs.

Entering the reactor, Zack confronts Sephiroth as the SOLDIER destroys Jenova's mechanical likeness, and the two briefly battle, with Sephiroth prevailing and throwing Zack out into the antechamber. Soon after, Cloud arrives at the reactor, having followed Tifa's cat and Zangan, to her. After seeing the prone forms of both Tifa and Zack, he picks up Zack's Buster Sword and attacks Sephiroth while he was off his guard, stabbing him in the stomach. While Sephiroth was greatly weakened, Cloud takes the opportunity to return to Tifa and carry her aside. The two share a brief moment before Sephiroth shatters Jenova's tank and seizes her head. Unable to move, Zack urges Cloud to finish him off, and Cloud charges, only to be impaled and thrown into Jenova's chamber. Stabbing him again and lifting him into the air, Sephiroth holds Cloud aloft at the reactor entrance over a pool of Mako. Cloud summons a last burst of will power and, using the sword impaled in him as a lever, throws Sephiroth into the Lifestream with Jenova's head.

Tifa's instructor Zangan, who was still searching for survivors in the town, finds Tifa, Zack and Cloud in the reactor and carries Tifa to safety, however upon his return members of Shinra and the Turks had arrived to retrieve Cloud and Zack. Professor Hojo learns of what Sephiroth has done and puts his "Jenova Reunion Theory" into action, injecting the survivors, including Zack and Cloud, with Sephiroth's cells, turning them into Sephiroth Clones. The town is rebuilt to cover up the incident, with Shinra employees hired to play the part of the townspeople. Shinra seals Sephiroth's records and he is declared missing in action, although many assumed him dead.

Development
According to the Final Fantasy VII Ultimania Omega, during the development of Final Fantasy VII, there were plans to have an Non-player character in Nibelheim tell a fabricated version of the Nibelheim incident so as to explain the event to the general public. According to an NPC in the town, Shinra built the Mako Reactor at Mt. Nibel twenty-five years before the start of the game, and five years ago the townspeople ran Shinra out of town and took control of the reactor for themselves. President Shinra thus dispatched Sephiroth to the town to put down the uprising, and according to official records, he was killed. There would have been an option, however, to tell the NPC the events are not true, but he does not listen. Another cutscene involved Tifa telling Aerith the true events of the town's destruction, and Aerith agreeing to help Tifa keep them secret from Cloud.

Crisis Core -Final Fantasy VII-
Crisis Core -Final Fantasy VII- retells the Nibelheim incident through Zack Fair's eyes. The journey to the reactor with Tifa Lockhart, Cloud Strife, Zack Fair and Sephiroth are the same as told in Final Fantasy VII, until Zack and Sephiroth arrive at the door to Jenova's chamber. At this time, Genesis Rhapsodos, the game’s antagonist, appears to goad Sephiroth into his break-down where previously it was the sight of the humanoid monsters in the tanks that had set off his descent.

Before Crisis -Final Fantasy VII-
Episode 12 of Before Crisis is a basic retelling of the event from the point of the player Turk, who was sent to Nibelheim by Tseng to check on a problem at the reactor. After parachuting onto Mt. Nibel the Turk meets and saves Tifa Lockhart from a group of monsters. In payment she serves the Turk as a guide up the mountain to the reactor. As more monsters are encountered around the reactor, Tseng orders the Turk to pull back and, after taking a secret cable car down the mountain, the Turk is told that President Shinra has sent Sephiroth to the town to lead the investigation over the increase in monsters around the reactor. The Turk hires Tifa to help Sephiroth up the mountain once he arrives. As the player rendezvous with Sephiroth, Zack Fair and Cloud Strife in Nibelheim, Cloud begs the Turk not to tell Tifa he is. The next day, the Turk stays behind in town while the group investigates the reactor. Sephiroth then returns and locks himself in his room at the inn without explanation for days. The game then shows Nibelheim ablaze, with Tseng ordering the Turk to follow Sephiroth to the reactor and find out what he was doing. Arriving at the reactor before Zack and Tifa, the Turk confronts Sephiroth, but is knocked unconscious. The Turk regains consciousness as Cloud arrives. Zangan takes Tifa to safety while the Turk enters Jenova's chamber. Cloud throws Sephiroth aside, but he still succeeds in claiming Jenova's head and leaps into the Lifestream to escape.

During the first part of Episode 13, the Turk and Tseng assist Shinra in cleaning up evidence of the incident and helping Professor Hojo set up the Jenova Project, which includes a brief exploration of the Shinra Mansion.

Last Order -Final Fantasy VII-
The OVA Last Order -Final Fantasy VII- retells the Nibelheim incident after Sephiroth's attack on the town in flashbacks as Zack Fair and Cloud Strife flee Shinra militia during their escape from Hojo. The OVA was released as a bonus feature with the film Final Fantasy VII: Advent Children, but was not dubbed in English for its Western release, only subtitled. The incident's depiction in Last Order takes many liberties with the story; various characters interact in different places, and new scenes are present, for example, Tifa being conscious and talking to Cloud at the reactor.

Final Fantasy VII: Advent Children
The Nibelheim incident is briefly alluded to in Final Fantasy VII: Advent Children. Sephiroth's scene of standing among the fires of Nibelheim, and the destruction of the Jenova likeness and her containment inside the reactor, are just a few of the many scenes from the game that are recreated. In Final Fantasy VII: Advent Children Complete, Sephiroth stabs Cloud with the Masamune and lifts him into the air, paralleling the ending of their battle at the reactor.

Dissidia Final Fantasy
In the first revealed trailer for Dissidia Final Fantasy, a plume of fire bursts from the ground, and Sephiroth emerges from it and prepares to battle the Warrior of Light. The scene of this confrontation is reminiscent of Sephiroth standing amongst the flames of Nibelheim. This allusion is continued in the game’s intro FMV where the entire villain cast is standing amongst the fire alongside Sephiroth. In Sephiroth's EX Burst Supernova, his opponent is consumed in a wave of fire from an exploding star. As the animation for the attack ends, the camera pans out to reveal Sephiroth standing in front of the fire, similar to his pose in the flames of Nibelheim.

Trivia

 * The incident takes place between September 22nd and October 1st, 0002, of the game’s timeline.
 * The incident was initially told from Cloud's point of view as himself as a member of SOLDIER. However, Sephiroth and Tifa later reveal Cloud's recollection is faulty and the true sequence of the events involved Zack Fair as the SOLDIER member. This is due to a Mako-poisoned Cloud having impressed Zack's memories onto his own, leading to a memory of the incident in which Cloud takes Zack's place.
 * Due to numerous retcons the order of some events and the proper way they unfold are unclear:
 * In Final Fantasy VII, Cloud is shown to pursue Sephiroth and Zack to the reactor immediately after awakening from unconsciousness. However, in the OVA Last Order -Final Fantasy VII-, Cloud offers to stay in the village and help the surviving villagers while Zack pursues after Sephiroth alone; with Cloud then following some time afterward.
 * In most iterations Cloud throws Sephiroth into the pool of Mako, however in Last Order -Final Fantasy VII- and Before Crisis -Final Fantasy VII- he jumps in voluntarily.
 * In Before Crisis -Final Fantasy VII-, Zangen retrieves Tifa shortly after Cloud arrives at the reactor, however, in most other tellings of the event he doesn’t retrieve her until well after Sephiroth’s “demise”.
 * Crisis Core -Final Fantasy VII- retells the events of the initial reactor inspection, differing from the original depiction from Final Fantasy VII with the inclusion of the character Genesis Rhapsodos.
 * Before leaving to inspect the reactor, a local villager snaps a picture of the Zack, Sephiroth and Tifa together as a memento of the occasion.
 * While the incident remains hidden to the general public due to the cover-up. A reporter wrote an article - which Zack receives via email - regarding an unknown incident at the location, and also reported the sudden lack of the local spoken accent amongst the town’s inhabitants, which was previously native to the village and region.