Welf Crozzo, a human blacksmith and adventurer from Rakia’s noble Crozzo lineage, inherits both the family’s famed magic-sword crafting legacy and the Skill *Crozzo Blood*—a power awakened in childhood that forced him into forging these weapons. Resentful of magic swords as corrupting tools of fleeting power, he fled his homeland with aid from his former patron deity Phobos, determined to carve a path free from his family’s shadow. Initially apprenticing with the Hephaestus Familia to refine his craft, he grappled with the weight of ancestral expectations until joining the Hestia Familia through Bell Cranel. As their chief blacksmith, he prioritizes durable, non-magical armaments, though he later accepts his capacity to forge magic swords under Hephaestus’s mentorship, crafting them solely for Familia allies. His arsenal includes *Crozzo Blood*—granting unmatched magic-sword potency—and *Veritas Burn*, enhancing strength and crafting precision. The anti-magic flame *Will-o-Wisp* disrupts enemy spells, while innovations like *Shikou Kazuki* produce unbreakable blades fueled by a wielder’s magic, redefining Crozzo techniques to reject their brittle, single-use predecessors. Pivotal battles against the Black Goliath and Amphisbaena tested his magic swords’ strategic value, while during the Xenos incident, he shielded allies like Lido and subdued powerful foes, underscoring his evolution as a warrior-artisan. Rivalry with Allen Fromel and tutelage under Tsubaki Collbrande sharpened his skills, while silent admiration for Hephaestus fuels his drive to earn her recognition. Pride in his work marries humility; he casually bestows clumsily named weapons on comrades, trusting them to rebrand his creations. A steadfast voice of reason within the Hestia Familia, his loyalty is unwavering. Though stubborn, he adapts ideals to protect others, gradually embracing collaboration. Lingering noble habits—like violin mastery—surface occasionally, though he masks them beneath a rugged exterior. From rejecting his heritage to transcending it, Welf reimagines the Crozzo legacy through practical innovations like Salamander Wool and Undine Cloth armor, prioritizing enduring utility and team survival over transient power. His journey embodies a craftsman’s rebellion, transforming inherited burdens into tools for collective resilience.