Cid is a young, blond-haired technician with violet eyes and a distinctive electronic visor on his forehead, serving as a minor but significant character. As the iteration of the recurring Cid archetype in this story, he departs from the traditional elderly mechanic persona by being noticeably youthful, yet he retains the exceptional mechanical wizardry the name is known for.

His background is largely shrouded in mystery, though it is known that his original world was destroyed, leaving him as one of its likely sole survivors. After the organization known as the Comodeen recognized his extraordinary engineering talents, they recruited him to assist in their war against the forces of Chaos. In terms of personality, Cid is generally cheerful, optimistic, and energetic, dedicating nearly all his time to building, maintaining, and piloting his many inventions. He possesses a very unusual and pronounced habit of bestowing female names upon all his machines, such as Jane, Catherine, and Silvia, and he treats these creations as though they were living, breathing beings. This deep emotional attachment means that when one of his inventions is damaged or destroyed, his normally timid and gentle demeanor vanishes instantly, replaced by a furious rage. In this state, he activates a powerful offensive ability known as the "Ultimate Hammer," unleashing giant mechanical hammers from the pack on his back to pulverize the source of the threat. Beyond his technical expertise, he is also well-versed in the esoteric phenomena of Wonderland, including substances like flight water and Soil, which are mysteries to most other characters.

Cid's role in the story evolves as the narrative progresses. In the first half, he is often found near the Comodeen, working on gadgets in the background. However, he becomes far more influential in the second half when he acts as the pilot of the submarine named Jane. His primary motivation driving his major actions is a grand engineering project: to reach the location of Teros to harvest rare flight water, which is necessary to power his true pride and joy, an airship called Silvia. He frequently provides essential assistance to the protagonists and the Comodeen, solving seemingly impossible problems through his inventions, such as constructing the airship for an assault on a flying fortress or hacking into defensive satellite systems. He develops key relationships with the other members of the Comodeen, who become a surrogate family for him after the loss of his own world. He also forms a bond with the twin protagonists and their guardian, offering them transport and aid, and at one point develops a minor crush on a character named Miles following a peculiar incident where she nearly ate him while he was transformed into a frog.

Cid possesses a remarkable catalogue of inventions, each with a distinct purpose. Among the most notable are the submarine Jane, which serves as the primary mobile base for the second half of the story; the airship Silvia, his ultimate dream project; and the interdimensional train Elizabeth, which is powered by a shard of the entity Omega and appears to have a degree of sentience. His other creations include a water sled named Catherine, a healing machine called Genevieve, and a clock-like device named Isabelle worn by the creature Chobi. For his attacks and technical work, he utilizes a mechanical pack on his back equipped with a keyboard and projection screen, as well as small mechanical arms that emerge to assist with repairs or hacking. His Ultimate Hammer attack is triggered by intense anger, typically only when his beloved machines are harmed, and is accompanied by a laser fired from his visor.