Kaseki

Kaseki is enthusiastic, warm, competitive about his craft, and almost childlike whenever presented with a technically demanding project. Years of producing the same types of tools for Ishigami Village have not dulled his love of making things; instead, Senku Ishigami's inventions give him an outlet for skills that had never previously been pushed to their limit.

He takes enormous pride in craftsmanship but rarely treats expertise as something to hoard. Kaseki readily works beside Chrome, teaches through example, and becomes excited when younger craftspeople develop new abilities. He has little patience for the idea that age should prevent him from taking part in strenuous work.

His recurring physical gag reflects that intensity: when sufficiently excited, the heavily muscled body hidden beneath his small elderly frame bursts through his clothing.

Kaseki's greatest ability is craftsmanship built through decades of accumulated experience. He can work wood, metal, glass, ceramics, fibers, gears, mechanical assemblies, and increasingly precise scientific components. Senku can often provide only the scientific principle or design, trusting Kaseki to work out how to manufacture the actual object with Stone World tools.

Glassworking becomes one of his first major specialties under Senku. After seeing the material and learning its properties, Kaseki quickly progresses from rough attempts to producing laboratory vessels and other complicated shapes. He later contributes to steam engines, generators, vacuum tubes, automobiles, ships, optical equipment, communications hardware, and countless smaller parts.

His hand control is precise enough for delicate work while his surprising physical strength lets him perform heavy forging and construction. Much of the Kingdom of Science's technological progress depends on the combination of Senku's theoretical knowledge, Chrome's improvisation, and Kaseki's ability to physically manufacture their ideas.

Kaseki becomes directly involved with Senku's group during the effort to create medicine for Ruri. Producing laboratory-quality glass requires an artisan beyond Senku and Chrome's own abilities, leading them to recruit the village's elderly craftsman.

The project immediately captures Kaseki's imagination. What begins with glass develops into a permanent partnership as Senku introduces increasingly advanced technological roadmaps and Kaseki repeatedly turns them into usable machines.

During preparations for conflict with the Tsukasa Empire, Kaseki helps manufacture the communications equipment and vehicles needed by the Kingdom of Science. The Age of Exploration expands his workload dramatically as shipbuilding, engines, textiles, currency production, food processing, and navigation all demand specialized tools.

As the Kingdom of Science begins crossing the world and rebuilding industrial infrastructure on multiple continents, Kaseki remains one of its principal manufacturing specialists, contributing to projects on a scale far beyond anything possible in Ishigami Village.

Senku Ishigami provides Kaseki with the scientific challenges that reignite his passion for crafting. Their partnership becomes one of the foundations of the Kingdom of Science.

Chrome is Kaseki's closest fellow craftsman and scientific collaborator. Kaseki respects Chrome's creativity despite the younger man's lack of formal technical knowledge.

Suika frequently assists around the Kingdom of Science and shares a warm relationship with Kaseki.

Ryusui Nanami repeatedly demands ambitious machines and infrastructure from Kaseki, giving the craftsman additional opportunities to work at larger scales.

Francois collaborates with him whenever food preparation, textiles, furnishings, or other specialized products require new equipment.