Sephiroth is one of the main villains in the Final Fantasy series. He is Cloud's arch nemesis also known as The One-Winged Angel.
Sephiroth's father was a scientist named Professor Hojo. When Sephiroth was still in the womb, Jenova cells were injected into his embryo as a experiment. The results of the experiment was it granted him powers beyond their imagination.
Sephiroth grew up and became one of the best SOLDIERS in the Shinra army. There he met several characters but, the most important one of all was Cloud Strife. Cloud had been a low ranking SOLDIER who went on a mission with Sephiroth with another first class SOLDIER named Zack Fair. The men were headed to a Mako reactor in Cloud's hometown of Nibelheim. They took care of the problem in the reactor quickly but, they discovered failed experiments through out the reactor. Sephiroth then saw his mother Jenova in a experimental pod. At that very moment he knew that he was just another experiment. When this happened his life went straight down. He read logs from the failed experiments alone 24 hours of the day. All this is what corrupted the mind of the best SOLDIER in Shinra.
Soon after Sephiroth learned of the cruel experiments done to him inside the womb he began to hate Shinra itself, and soon the entire planet. It wasn't long until Sephiroth's true evil side started to show. He started to kill the residents of the small village. He then began to set buildings on fire and destroy everything in his path. Cloud awoke to find his home burning and finds his mother dead under the flames. He then rushed up towards the reactor. Tifa made her way up also and found that her father was dead. She tried to kill Sephiroth but, he hit her down and Zack was soon taken down to. Why Sephiroth was busy with those two Cloud had arrived. He saw his two best friends on the ground. He quickly picked up Sephiroths sword. He ran towards Sephiroth and caught him off guard. He stabbed Sephiroth and saw that Sephiroths sword was in his shoulder. Cloud reacted quickly and kicks Sephiroth back of the platform apparently making him fall into the lifestream. Cloud goes to his friends only to find that Jenova's head had been cut off.
After all this happened Shinra tried to fix up everything. All of the villagers that had died were replaced by Shinra workers. All files of Sephiroth were destroyed ans they acted like nothing happened. Sephiroth's father Hojo had been experimenting on Jenova(whats was left of her) and tried to figure out what she really was. Sephiroth wasn't seen for a long time. Cloud at this point was captured by Shinra after trying to save Aerith who they thought was the key to the promise land. So Cloud was locked up in a cell and so was his the Avalanche group. But, at night Cloud found that his cell door had been opened. He jumped out to find blood covering the ground. He released his crew and they searched the place. They found the head of Shinra killed with Sephiroths sword still inside him.
So the Avalanche Group goes after Sephiroth. Once Cloud was on a small ship that was leaving the area when Sephiroth shows up. Dead bodies covered the ground Cloud stood on from Sephiroth. But, the meeting was cut short when a monster appears and fights Cloud. Sephiroth heads out and Cloud still wanted revenge. So Cloud returned to Nibelheim and what he found was shocking.
When he returned everyone had acted like nothing bad had ever happened. Everything was normal which was odd to Cloud so he went back to the Shinra mansion where he was held for experiments. When he reaches it he finds Sephiroth. But, Sephiroth escapes from Cloud. While in Nibelheim Cloud meets a strange man who goes by Vincent Valentine.
Cloud was building his crew up while Sephiroth tried to gather black materia. It is later found out that Sephiroth had been making small clones of himself to fight Cloud. Cloud meets several people like Cid Highwind and another girl who goes by the name Yuffie. He finds her at Centra Ruins and obtains the black materia there that Sephiroth was looking for. But, right when Cloud aqquired the materia Sephiroth shows up. Sephiroth looks toward Cloud and starts to manipulate him. He makes Cloud come over and give him the materia. Thus giving Sephiroth absolute power. This gave Sephiroth the power to try and achieve his goal of ultimate destruction. Sephiroth then tried to make Cloud kill Aerith but, he resisted. So Sephiroth took his blade and killed her. This made Cloud an emotional wreck.
Cloud who upset for what had happened and for what he had just done decided that him ans his crew needed to reach the home of Centra. They wanted to go after the white materia to defeat Sephiroth. So Cloud made his way to the North Crater. This is where Sephiroth is and is waiting for Cloud. Sephiroth began to prepare the materia for the creation of Meteor.
Once Cloud had finally made it to the North Crater as predicted Sephiroth was waiting for him. Sephiroth right when Cloud arrived started to play with his mind. He began to give Cloud different flashbacks and finally revealed that when Zack died that he had gone crazy and thought his memories were his. Cloud couldn't handle what he was just told. He couldn't fight like this. He suddenly disappeared along with his crew. The crater protected by a force field Sephiroth created covered him. So everyone but Cloud recovered started to make plans. But, they still couldn't locate Cloud.
Eventually everyone regroups including Cloud and they rush towards Sephiroth. Fighting tons of enemies laid out by Sephiroth. Sephiroth's meteor was going hit earth and all hope was seemed to be lost. Sephiroth had become the ultimate evil and was going to destroy all humanity. Sephiroth set the meteor off and it was headed right towards them. But, Cloud wouldn't go down without a fight. Him and his crew come after Sephiroth and begin to fight him. Sephiroth forms into this monsterious being and The Avanlanche must now fight it. After a hard fight they finally beat him in this form. But, Sephiroth wasn't finished. He teleported him and Cloud to some unknown place for one last battle. Cloud in a hard battle finally defeats him with a omnislash. After all that had happened Cloud's memories had been restored. He then took out the meteor making everything peaceful once more but, for how long.
Sephiroth makes an appearance in Kingdom Hearts II as a villian. During the story Sephiroth tries to get the keyblade. He talks to Sora to see if he defeated him could he wield the blade. Sephiroth then begins to attack Sora and tries to get the Key Blade several times. He knows that the blade is the strongests of all blades. Sephiroth is defeated though by Sora.
Sora then tells him he can never wield the blade. Since he couldn't have the blade he wanted Cloud. So he sent a message to Cloud to come face him. Cloud shows up and they start to fight. The two have a great battle. Cloud becomes even powerful and as the fight got even better they both disappear. Tifa and Sora go off looking for Cloud to see what happened.
In Advent Children it explains about where Cloud is after he defeated Sephiroth. But, soon he finds that three men Kadaj, Yazoo, and Loz are looking for the remains of Jenova. Towards the end Kadaj who is kinda the leader of the group gets Jenova. He then drinks it and tells Cloud "are you ready for my reunion". Cloud jumps after Kadaj but, is to late Kadaj has become Sephiroth. Cloud and Sephiroth then battle a hardcore battle. Sephiroth starts to win and stabs Cloud in the Shoulder. But, right when you think Sephiroth has it Cloud preforms and version 5 omnislash and defeats Sephiroth. Before Sephiroth dies you hear Cloud say "stay in my memories where you belong". Sephiroth then responds " I will never be a memory". He then disappears and Kadaj falls from the air and eventually goes into the lifestream. Cloud is then shot by the almost dead Yazoo and Loz. The two brothers enter the life stream but, as Cloud is about to the dead Aerith and Zack Fair stop him from going in and its a happy ending. Well not for Sephiroth at least.
Final Fantasy VII: Advent Children
Set two years after the events of the game, Cloud Strife and his friends must discover the mystery of the plague called "Geostigma".