Leen is a fairy elder who appears in the anime In Another World With My Smartphone. She is over six hundred years old, often describing herself as six hundred and twelve, and belongs to the fairy folk. In public, she conceals her wings using light magic. Leen was originally the tribal chief of the fairy tribe living in the Kingdom of Mismede. After meeting the protagonist Touya Mochizuki, she becomes the court magician of Brunhild Dukedom and eventually becomes one of Touya's wives, serving as the fifth queen of the duchy.

Leen is a highly accomplished magician. She can wield six of the seven primary magic elements, lacking only the darkness element, and she also has great proficiency in non-elemental spells such as Program, Transfer, Protection, and Discovery. This magical expertise leads to her role as the teacher of Charlotte, the royal court mage of Belfast. She is almost always accompanied by a enchanted teddy bear named Paula, which she controls using her null attribute magic.

Her personality is that of a knowledgeable and experienced elder, though she carries herself with a calm and composed demeanor. She is motivated by a desire to support Touya and lend her magical knowledge to his endeavors. Leen develops a close relationship with Touya, and her position evolves from a foreign fairy chief to a trusted advisor and partner within Brunhild. She also interacts with Touya's other companions and wives, bringing a sense of ancient wisdom and maturity to the group. Her notable abilities include her mastery of multiple magic schools, her skill with null attribute magic, and her long life experience, which makes her a valuable guide in magical and political matters.