- "Oh, you know of him? He's my grandfather. Grandpa is so awesome! When he's researching, he's unstoppable - he never gives up until he's found the solution!"
Professor Cid Previa (シド・プリヴィア, Shido Purivia?) is a non-playable character in Final Fantasy V. Cid is an elderly inventor and scholar from Karnak, and a researcher into the Crystals. Together with his grandson Mid who researches at the Library of the Ancients, Cid is one of the foremost inventors in the world.
After researching the Crystals, Cid developed machines that could produce more energy from them. With the use of the machines, Karnak became one of the most powerful and prosperous kingdoms in the world. Excessive use of Cid's machinery, however, was damaging the Crystals' structural integrity and when Cid discovered this, he attempted to shut down the machine in Karnak, but was imprisoned. He is later freed shortly after the Warriors of Light were imprisoned.
The four fail to save the Fire Crystal, and Cid goes to the pub in Karnak to sulk. The party travels to the Library of the Ancients and meet Mid, who is outraged to hear Cid's state. Mid smacks Cid back to his senses, and using a book he found in the library, the two refit Karnak's Fire-Powered Ship to run without the Crystal or the wind, allowing the party to travel the world to attempt to save the remaining Crystal. The ship is later supposedly destroyed in a whirlpool, but the party make it back to the Library of the Ancients. Cid and Mid tell the party they saw King Tycoon in the desert to the west, and provoke a Sandworm attack to allow the group to enter the desert to search for him.
While the party explores the city beyond the desert, Cid and Mid fly the black chocobo they left behind to its home where they fall into a pitfall, and meet up with the party who has also fallen into a trap. The group then find the Fire-Powered Ship, which escaped harm, and an ancient airship, which Cid activates. When the Ronka Ruins lift off, Cid and Mid tell the party how to infiltrate the vessel and find the Earth Crystal, and retrofit the airship with Adamantite so it can fly up to the ruins. Afterward, the two tell the party how to open a portal to Galuf's world using the crashed meteorites.
After the Light Warriors put a stop to Exdeath's plans, Cid had all the papers and knowledge he had accumulated about the Crystals destroyed so that no one else might misuse them while he took the secret to utilizing their power to his grave. The demon Ra Devil was determined to use the Crystals for his own plan and thus took Cid's brain from his grave. Mid Previa tried to protect his grandfather's grave but was killed by Ra Devil.