Kaijin, a dwarf craftsman from the Dwarven Kingdom, once helmed the Palace Knights’ Workshop Team, earning widespread acclaim for his masterful forging and engineering prowess. Though not of noble birth, his reputation flourished across dwarven and human realms alike, blending traditional craftsmanship with inventive research to drive technological and infrastructural progress. Exiled following a clash with former rival Vesta, he allied with Rimuru Tempest, relocating to the Jura Tempest Federation with lifelong companions Garm, Dold, and Mildo—experts in textiles, tools, and construction, respectively. Initially devoting himself to weaponcraft, Kaijin gradually shifted to overseeing Tempest’s technological evolution, spearheading the integration of electricity, plumbing, and innovative architecture that propelled the settlement into a bustling metropolis. A pivotal chapter in his journey saw him reconcile with Vesta, partnering to pioneer the revolutionary Spirit Magic Core—an achievement embodying his faith in redemption and collaborative ingenuity. Later, he extended his impact by aiding the construction of a new city within Milim Nava’s domain, cementing his reputation as a trusted innovator beyond Tempest’s sphere. Kaijin’s personality combines diligence, loyalty, and a grounded intensity. Though gruff when focused on work, he champions communal advancement, prioritizing client needs and mentoring emerging talent. His ability to unite artisans and scholars under shared goals, paired with resilience against past adversities, has solidified his role as a cornerstone of Tempest’s ever-expanding technological ambitions.