Lotte Jansson is a Finnish girl of below-average height with pale skin and freckles across her cheeks and nose. She has short, bright orange hair, sometimes appearing blonde in certain lighting, held back by a navy-blue headband, and turquoise blue eyes. Lotte wears semi-rimless mauve eyeglasses with large round lenses that strongly magnify her eyes. Her Luna Nova uniform is customized with a red belt and a red band on her hat, and when out of uniform she continues to wear a blue headband.

Lotte is shy, gentle, and soft-spoken, rarely showing anger and often acting as the emotional support of her group. She is deeply kind-hearted and consistently looks out for Akko, frequently worrying that Akko’s single-minded determination may cause her to overlook her own safety or the feelings of others.

Though usually timid, Lotte is capable of firm resolve when pushed. She can become visibly upset when something precious to her is hurt, as seen when Akko damages her ancestral sheet music, yet she remains forgiving and loyal. When necessary, Lotte is also able to stand up for herself and her friends, displaying surprising courage and determination. Beneath her quiet demeanor lies strong conviction, devotion to her friends, and a sincere love for magic, music, and faerie folklore.

As a witch-in-training, Lotte possesses solid foundational magic, including Flight Magic using a broom and Metamorphosis Magic, allowing her to transform herself or others into animals and alter or enchant clothing.

Her greatest strength lies in Communication Magic. Born into a family of spiritual magic users, Lotte can invoke and communicate with spirits residing in old objects and understand faeries. Unlike most witches, she often performs this magic through a traditional song taught by her grandmother rather than direct spellcasting. This song is powerful enough to calm large groups of faeries, as shown in The Enchanted Parade.

By working in harmony with faeries and spirits, Lotte can also amplify her magic, enabling advanced techniques such as manipulating nearby plants, generating twin magic circles that create a strong healing field, and forming a wide-area purifying barrier that cleanses impurities, damages hostile enemies, and can induce them into a deep sleep through her spiritual conduits.