Majolica le Fay, also called Majo, acts as the resident inventor and scientist for the Otogi Bank. Her character draws inspiration from the legendary Arthurian sorceress Morgan le Fay. She possesses long blond hair reaching her waist and distinctive purple eyes, often hidden behind thick, swirl-patterned glasses. Her signature look includes a long black coat, a large pointed witch-like hat, tights, and a hair ribbon. Sources conflict on her height, reporting both 152cm and 167cm.

Within the Bank, Majolica specializes in crafting unconventional devices, notorious for their impracticality or flaws despite occasional usefulness. Her inventions include Ryoko Okami's Neko-Neko Knuckles—cat-shaped, taser-equipped gauntlets that meow—and strategically deployed stink bombs. These gadgets typically feature design quirks, forgotten functions, or technical shortcomings that frequently cause complications during operations.

Majolica displays a bubbly eccentricity marked by a unique speech pattern and enthusiastic dedication to her scientific work. She maintains a near-constant lollipop habit, always carrying them and rarely seen without one. Among Otogi Bank members, she shares a particularly close bond with Otsu Tsurugaya. She is friends with all core members: Ryoko Okami, Ringo Akai, Ryoshi Morino, Liszt Kiriki, Alice Kiriki, Tarou Urashima, and Otohime Ryuuguu, while maintaining adversarial relationships with Shirou Hitsujikai and Reiko Kokonoo.

Her role remains steadfastly focused on providing technological support through her inventions for the Otogi Bank's activities.