When the party arrives at Phon Coast on their way to the Imperial City of Archades, Balthier reveals his past to Ashe and we find out that his father is no other than Dr Cidolfus Demen Bunansa, whom we had earlier seen in the company of Vayne. It is the first time seeing the Cid character, who appears or is mentioned in every Final Fantasy game, as a villain, and a boss enemy at that. However he still shares the trait of researcher and inventor with most of the previous Cids. Here is what the game's bestiary has to say about the doctor;

"Chief of the Draklor Laboratory, the top-secret weapons laboratory of the Archadian Empire. Full name: Cidolfus Demen Bunansa, Age: 58 Pusues a program for manufacturing nethicite, a variety of magicite with the property of absorbing magickal energy. Friend to Vayne. Though their ages are different they share many of the same ideals and beliefs. Rook Dr Cid has been working on developing thought-driven combat weapons, called "rooks", for some time now. Test models saw their first combat use in a recent incident at Draklor Laboratory. Three models have been produced based on data collected during the Draklor Laboratory incident. Draklor CB56 Remora Fighter Small fighter airship of the Imperial Army. Gun turrets glaced on the keep, and turrets on the deck make this an effective weapon against air and ground threats. A mainstay of the Imperial Armored Forces together with the newer Cb58 Valfarre fighter. The initials of the chraft's designer, Dr Cid, adn the year of it's production adorn the hull."

It was around six years ago that Doctor Cid let his studies of nethicite consume him. His research led him to the holy city of Giruvegan, where he came in contact with the Occuria, godlike creatures who pull at the strings of Ivalice from the shadows by granting the power of nethicite to people like Ashe's ancestor Dynast-King Raithwall. He ended up teaming up with one of them, called Venat, who rebelled against the other Occuria and their ways. Venat taught Cid how to manufacture nethicite which made him only crave more for the power and the dream of getting "The reins of history back in the hands of man". This dream and the nethicite was the only things Cid constantly rambled on about.
In the end Cid's obsession with power and prestige made his son run for the skies.

Cid pretty much classifies as the evil mad scientist. He even does the lunatic laughter while holding his hands high up in the air. He often seems to speak to himself, although it is actually the invisible Venat, who stands behind him, with whom he is talking.
Cid's speech and body movements are very dramatic at times. He gets excited and speaks with big words about nethicite and the power it holds.

Balthier lost his father to the nethicite and fled but as he is drawn into Ashe's search for the stone and her struggle to free Dalmasca from the Archadian Empire, he must once again face his past.
The party encounter Dr Cid for the first time in the Draklor Laboratory, in search of the Dusk Shard. Balthier's and Cid's dialogue is filled with bitterness. They both have illfeelings about one another; Balthier is angry at his father for sinking so low for the sake of prestige and power, neglecting him and taking away his freedom along the way, and Cid is disappointed because Balthier decided to leave the life he had set for him.

Despite the anger they both hold, their bond as father and son remains. I believe they still care for one another, beneath it all. After the second and final battle with Cid, Balthier rushes forth to help his father and gives him a pained facial expression. In the end their relationship was unrepairable. Cid put his ideals before his family... only Square Enix knows if this was done with good intentions. Maybe he only wanted to give Balthier a good life by making him a judge, perhaps he felt that his son rejected his love when he fled that life. Perhaps not.
All I know is that Dr Cid turned out to be a pretty sympathetic villain and the interaction between him and Balthier was the most interesting point in the game for me.