Cid is the regent (king) of the nation-city of Lindblum in the JRPG Final Fantasy IX.
After Zidane Tribal kidnaps, or "rescues" Princess Garnet, it is realized by Garnet that Cid was the one who ordered Tantalus to kidnap her. The reason for kidnapping her was because of Garnet's mother, and her increasingly erratic and violent behaviour.
Cid is Garnet's uncle, brother of her father, the King of Alexandria, who passed away in the game's backstory.
When Zidane and company first meet Regent Cid, he is in the form of an Oglop. It is revealed that his wife, Hilda, whom he named the airship Hilda Garde
after, is a mage, and after finding Cid with another women, she used her magic to turn him into an Oglop before she left him. Later in the game, Cid finds an antidote to recover himself and turn himself back to human form. Unfortunately, this backfires, and Cid is instead changed into the form of a frog, arguably an upgrade.
Eventually, Hilda is located, and after they reconcile, she returns him to his former glory as a human. In his human form, he is able to complete work on more upgraded airships, particularly the Hilda Garde III
In the end, Cid and Hilda adopt Eiko
as their daughter, and they live happily ever after in Lindblum.