Therese Alexanderite, a Jewel race member from an alternate world, wields Jewel Magic fueled by gemstones, her power scaling with their quality and refinement. Accessories forged by Naofumi Iwatani elevate her magic to rival Legendary Heroes, amplifying her combat prowess. Her ivory skin, cyan hair shimmering under sunlight, and light-blue eyes—shifting hues during spellcasting—complement her gemstone-adorned bangles. Introduced as L'Arc Berg Scythe’s companion, she travels with him and Glass to another world, tasked with eliminating its Legendary Heroes to safeguard their own. During the Cal Mira activation, her party unknowingly allies with Naofumi’s group to level up, later commissioning him to craft a bracelet whose exceptional craftsmanship sparks her obsession with his creations. Reserved and courteous, she contrasts L'Arc’s levity, treating her gemstones as sentient allies—communicating with them and honoring their sacrifices in battle. This reverence extends to finely crafted jewelry, evolving into fervent admiration for Naofumi’s work. Her growing zeal alters her demeanor, earning the moniker "Motoyasu III" for her boisterous enthusiasm. A tactical innovator, she devises strategies like leveraging Naofumi’s accessories to convert enemy jewel users into allies. Her fusion spells—"Thunder Rain Flying Circle," blending lightning magic with L'Arc’s scythe skills, and "Reverse Burning Snow Moon Flower," merging flames with Glass’ techniques—prove decisive in clashes against Kyo Ethnina and wave vanguards. Sacrificing Naofumi’s bracelet for tactical gains, then receiving enhanced replacements, underscores her deepening reliance on his craftsmanship and role in unifying heroes across worlds. Though her origins remain shrouded, her enduring bond with L'Arc stems from a shared quest tied to ancient legend. Initially wary of Naofumi, she transitions into a fervent collaborator, driven by mutual respect and a unified resolve to combat interdimensional threats, solidifying her place as a pivotal ally in cross-world alliances.