Origin: Early Life
Aerith was born to a the last full-blooded Cetra named Ifalna, and a Shinra scientist named Professor Gast at Icicle Lodge in the northern continents. Professor Gast met Ifalna when he quit his job at Shinra and moved to the northern continents to research about the Cetra. There he meets Ifalna, and she volunteers to help him research about her race. They eventually fall in love and two years later, Ifalna gives birth to Aerith. When Aerith was only 20 days old, Shinra soldiers attacked Icicle Lodge in an attempt to kidnap the Cetra. The Shinra soldiers were sent by Professor Hojo, a former assistant of Gast. The soldiers killed Gast and kidnaped Ifalna and Aerith. They were taken back to Shinra’s Headquarters in Midgar, and were used as test subjects. Shirna was attempting to learn more about the Cetra race and gain access to the “Promise Land". Seven later, Ifalna escaped from Shinra Headquarters and fled to Sector 7 with her daughter but died at the train station. A woman named Elmyra Gainsborough discovers Aerith and a dying Ifalna, who entrusts her daughter to Elmyra.
In the meanwhile Shinra continued to search for Aerith, who then became the last Cetra alive. As she grew up, Aerith started to inherit the Cetra abilities. She began hearing voices from dead souls that wandered the Earth, but since she never knew anything about her Cetra heritage, this frightened her. She decided to ignore it and not acknowledge it. For years Elmyra raised Aerith alone as her daughter in the slums of Sector 5, however Shinra eventually relocated her and attempted to persuade her to join Shinra willingly instead of capturing her, but Aerith refused.
As she grew up, Aerith spent a great deal of time in the Sector 5 Church. Due to the Mako Reactors draining the life out of Midgar and its surrounding plains, little plantation was able to grow in the area. However, Aerith managed to cultivate a flower patch out of the dirt under the church's floorboards.
Aerith first meets Cloud in the train station after the AVALANCHE had just blown up a mako reactor. Aerith was attempting to sell Cloud a flower, he tells her to flee from the area for now. Aerith then met Cloud again when he falls through the church roof and onto Aerith's flowerbed after a failed attack on the Sector 5 reactor. Cloud and Aerith begin talking a while, and she tells him that the church is the only place in Midgar that flowers will grow. Aerith then reveals to Cloud that she is being pursued by Shinra’s Turks, and asks him if he’ll be her bodyguard. Shortly after, the Turks shows up at the church, demanding Cloud to turn Aerith over. Instead, Cloud fought off Turks while Aerith safely exited through the back door. They successfully escape from the church and run across the rooftops back to Aerith’s home. Back there, she introduces him to her adoptive mother, Elmyra and Aerith explains to her that Cloud doesn't know his way around Midgar, so she wanted to help him get back to Sector 7.
On their way back to Sector 7, the two of them took a break in a playground. While talking to each other, they see Tifa being taken to Don Corneo’s place. The two decide to rescue Tifa. Cloud wasn't allowed access inside because he was a man, so Aerith gives Cloud a make-over and dress him up as a woman. With their new disguise, both of them were able to enter Corneo’s place undetected. They head to the basement and discover Tifa there, and Tifa tells them her plan about finding out what Corneo knows about Shinra. They successfully get the answers out of Corneo, and learn that Shinra knows where AVALANCHE is hiding. Shinra was also planning to destroy all of Sector 7 to rid them of AVALANCHE. Aerith, Tifa, and Cloud then leave and make their way to Sector 7. When the three of them arrive, they discover that the battle has already begun. Cloud and Tifa head up the tower to help their friends, while Aerith went to Tifa’s bar to get Marlene out of the Sector. Aerith was able to locate Marlene and took her back to her adoptive mother’s place. However, the Turks were waiting for Aerith and kidnapped her.
The Plan to Stop Sephiroth
Aerith was being held in Shinra Headquarter Labs. Cloud and company were able to locate Aerith and free her before she could be harmed. On the way, they also befriended Red XIII. Afterwards, they headed for the exit but were quickly captured before they could go anywhere. Everyone was then imprisoned. Later that night, Cloud wakes everyone up and alerts them about the dead guard outside of their door. The party follows the blood trail upstairs, where they discover President Shinra dead with Sephiroth’s sword impaled in his back. Cloud alerted everyone to head downstairs and that he will follow them. Aerith and everyone else quickly run downstairs and steal a truck so they could escape and headed for the outskirts of Midgar. Cloud protected everyone on the truck with his Buster sword while riding his motorcycle. They all eventually make it to the outskirts safely, and headed for the nearest city to rest up. At the inn, Cloud briefs everyone in on his past and Sephiroth’s plans to destroy the world. They all agree to stop Sephiroth. They head for Nibelheim to gain answers, but make a quick stop at Wutai where they meet Yuffie. They also make a quick stop for rest at the Gold Saucer, and meet Cait Sith here. When they finally arrive at Nibelheim, they end up gaining more questions. The party also meets Vincent Valentine in the Shinra Mansion basement. The last member of the party, Cid Highwind is met at Rocket City. Cid allows them to use his plane, the Highwind. When the party visits Red XIII’s home at Cosmo Canyon, Aerith learns more about her heritage and about the Cetra temple.
The party eventually learn that Sephiroth’s plan was to acquire a materia called the “black materia” which would allow him to cast a meteor to destroy the planet, and thus force the lifestream to expose itself to try heal the planet. He would then use that to gain access to the “Promise Land". Aerith and company were able to get to the black materia before Sephiroth, however Sephiroth forced Cloud into handing over the black materia. With the black materia in the hands of Sephiroth, Aerith decides to leave the party and stop him herself. She travels alone to the Forgotten City to use her white materia and caset Holy to repel the Meteor. Cloud and everybody else tracked Aerith to the Forgotten City, where they see her praying on an altar. Unknown to anyone, Sehpiroth was in the shadows, using similar mind control powers like when he made Cloud hand over the black materia. He attempted to force Cloud into killing Aerith himself, however Cloud was able to resist Sephiroth’s influences this time. Sephiroth then jumped down and killed Aerith himself. He stabs her through the heart with his sword, causing the white materia she wore on her headband to drop down into the water. Sephiroth then mocks Cloud, telling him he has no emotions and that he was not even human; just a puppet the whole time, trying to drive Cloud insane. Later Cloud gave Aerith a proper burial at the City of Ancients in the water, where she could reconnect with the lifestream.
It is later revealed to the party that Aerith had actually casted Holy before her death, and that she went to the Forgotten City to learn how to use the spell. She was successful in unleashing Holy before she died. The white materia was passed down from Cetra to Cetra, and thus from Ifalna to Aerith. However Sephiroth kept the Holy spell in check with his powers and blocked its effect. The party wanted to make sure that Aerith did not die in vain, so they must defeat Sephiroth for Holy to be unleashed. With this information, the party confronts Sephiroth for a final battle, to which they defeat his monster form. Cloud then battled Sephiroth in his normal form, and he defeats him with his Omnislash. With Sephiroth defeated, Holy was unleashed and attempted to repel the Meteor. As it seemed like Holy was not enough, the Lifestream rises and aids Holy pushing the Meteor far away enough to be destroyed. Aerith was seen in the Lifestream.
Two years after the defeat of Sephiroth, the planet has healed. The world was cursed with a diseased called “geostigma”. Aerith still remains in the Lifestream, guiding Cloud through difficult times. Cloud continues to blame himself for not being able to prevent the deaths of Aerith and Zack and no longer feels strong enough to protect anyone, and thus moves to Aerith’s church. Cloud eventually learnt to forgive himself. During the fight with Bahamut, Aerith appears to help Cloud by throwing him towards Bahamut. While Cloud chased after Kadaj, their battle goes through Aerith’s church, where the Lifestream water rises up and cures Cloud’s Geostigma. After Kadaj is defeated by Cloud, he and his brothers are accepted into the Lifestream by Aerith, who they call “mother.” Aerith has a final appearance at the end of the movie, where she is helping one of the children before leaving with Zack. She turns around and smiles at Cloud, to which he smiles back with the burden of guilt lifted from him.