Emilia is a beautiful half-elf with long silver hair and purple-blue eyes. She typically wears a white and purple outfit adorned with a white flower in her hair. Though she appears to be in her late teens, her true age remains unknown, with her mental maturity said to be in her early to mid-teens. Her hairstyle has varied over time, arranged by Puck, the Beast of the End, as part of their contract.

She has worn several outfits throughout the series, including a white cloak with cat ears enchanted with cognitive obstruction, used in early arcs and during her journey through the Augria Sand Dunes in Arc 6. During Subaru’s knight ceremony at the end of Arc 4, Emilia wore a white dress with a purple-lined mantle and floral hairpieces. She has also worn a yukata in Arc 5 and a wedding dress during her encounter with Regulus, which she modified for combat. In Arc 6, her attire closely resembles that of her aunt, Fortuna. As a child in Elior Forest, Emilia wore similar colors, with a light green ribbon, a different flower in her hair, and a light-purple headband.

Emilia is a kindhearted and selfless girl who always puts others before herself, though she tends to underestimate her own kindness and call it selfishness. She speaks with an old-fashioned tone, often using words like “dunderhead,” and stretches out the word “really” when talking about things dear to her, a habit she inherited from her aunt, Fortuna. Emilia values promises deeply and believes in the goodness of others, preferring peace and understanding over violence, though she will fight decisively if necessary.

Her main motivation stems from her desire to save the frozen elves of Elior Forest. After centuries of helplessly tending to them, Roswaal offered her a chance to become the 42nd monarch of Lugunica, which would grant her access to the Dragon’s Blood that might unfreeze them. Determined to create a kingdom free from discrimination, she accepted and joined the Royal Selection. However, Emilia often struggled with her emotions and feelings of isolation, relying heavily on Puck and later Subaru for support, which made her emotionally fragile and insecure at times.

Through her experiences, especially during the Sanctuary trials in Arc 4, Emilia faced her fears and learned to stand on her own. Subaru’s faith in her helped her rebuild confidence and confront her past, emerging more mature, strong-willed, and inspiring to those around her. Over time, she became bolder and wiser, taking charge even in danger and earning the respect of her allies. Though she remains innocent in matters of love, her bond with Subaru continues to grow, revealing a more assertive and emotionally aware side of herself.

Emilia possesses a rare and powerful affinity for spirits, allowing her to easily form contracts with them since childhood. She was once contracted with the Great Spirit Puck, who served as her protector and companion. After Puck severed their contract during the Sanctuary incident, Emilia’s pendant shattered, and she temporarily carried him in a crystal stone. She later replaced it with a purer glintstone from Subaru but still lacks the mana to fully restore their contract. Emilia can communicate with and command lesser spirits for various purposes, such as healing and combat support. Her spiritual arts grant her powerful control over ice and cold, capable of summoning ice spears, barriers, and even ice clones for both offense and defense.

In addition to her spiritual talents, Emilia wields exceptional ice magic derived from her natural fire attribute, converting heat into freezing energy. Her signature abilities include Al Huma, which unleashes massive ice pillars, and Absolute Zero, a devastating spell powerful enough to freeze time and nullify even the Divine Dragon’s breath. She also uses Ice Brand Arts, conjuring ice weapons for close combat and creating ice soldiers shaped like Subaru. Despite favoring magic, Emilia is also a skilled melee fighter, blending agility and ice manipulation for a unique fighting style. Her key equipment includes her new glintstone housing Puck and the Divine Dragon’s talon fragment, symbolizing her role as the administrator of the Pleiades Watchtower and her growing mastery over both magic and spirit arts.

About a century ago, Emilia lived in Elior Forest with her aunt, Fortuna, who kept her isolated in the “Princess Room.” Despite the loneliness, Emilia discovered her ability to summon lesser spirits, which she called fairies. One day, she met a man named Geuse, who often visited Fortuna, and became curious about a mysterious seal in the forest. Disobeying orders, Emilia found the seal and soon encountered Pandora, the Witch of Vainglory, and Regulus Corneas, the Sin Archbishop of Greed. Their arrival led to a devastating battle in which Fortuna fought to protect Emilia and the seal. Manipulated by Pandora, Geuse accidentally killed Fortuna and went mad, becoming the Sin Archbishop of Sloth. Overwhelmed by grief, Emilia lost control of her powers and froze the entire forest, sealing herself and the elves in ice.

Many years later, the ice melted, and Emilia met Puck, with whom she formed a contract. The two lived together in the snow-covered forest, avoiding outsiders due to the widespread prejudice against half-elves. Known as the “Witch of Frost,” Emilia suffered greatly from human hostility and even faced an attack from Melakuera, one of the Four Great Spirits. To protect her, Puck sealed her traumatic memories. Despite her hardships, Emilia remained kind and compassionate, surviving by trading magic stones for supplies while caring for the frozen elves who were connected to her past.

Eventually, Emilia met Roswaal L. Mathers, the first human who treated her kindly. Impressed by her spirit, Roswaal invited her to join the Royal Selection after the Dragon Jewel recognized her as a candidate, giving her the chance to save the people of Elior Forest through the Dragon’s Blood. This marked the beginning of her journey into the wider world, where she faced both prejudice and newfound allies.

In later years, Emilia gained respect through her leadership and courage. She participated in the Subjugation of the White Whale, took part in interviews to dispel public fears about her race, and led expeditions such as the Pleiades Watchtower mission. Despite discrimination and danger, Emilia continued to grow stronger, earning the trust of her companions and proving herself as a leader worthy of becoming the next ruler of Lugunica.