Místrúne Ásgrím, commonly known as Mist, is a noble Álfur hailing from the Kingdom of Ygvarland and the daughter of Viscount Ásgrím. She attends the royal academy, forming a close friendship with Yuna and Lukka. Despite her noble lineage, Mist displays no pretentiousness, maintaining a gentle and accommodating demeanor. Her social circle widens when she befriends Asuha, enabling a long-desired connection with the reserved Princess Astarotte, whom Mist had previously hesitated to approach.

Mist possesses a voluptuous figure with notably large breasts, attributed to being breastfed by Effie's elder sister Edda until age twelve. She has long peach-colored hair (blonde in manga illustrations), adorned with a ribbon—red in anime, green in manga—and golden eyes. Her pointy ears signify her Álfur heritage. She typically wears her school uniform and often appears without underwear. This habit becomes plot-relevant when she gifts her panties to Naoya Tohara as an apology, misunderstanding that men appreciate such items.

Her personality involves chronic misinterpretations and outrageous inferences, such as believing Asuha is Astarotte and Naoya's daughter. She frequently performs inappropriate actions like removing her underwear in public, driven by delusions about sexual matters. Despite these quirks, she is inherently good-natured and forges strong bonds with Asuha, Astarotte, Yuna, and Lukka. She develops an attraction to Naoya upon their first meeting but pursues no romantic relationship. Though timid compared to her friends, she exhibits loyalty and selflessness.

Key events include her role in reconciling Astarotte's initial isolation by leveraging her friendship with Asuha. During a visit to Astarotte's manor, Mist references her wet nurse Edda, revealing her prolonged breastfeeding history. In another incident, she offers cookies and her panties to Naoya, mistakenly believing it would please him while confirming her lack of underwear at that moment.