Krulcifer was discovered as a child by Stiyl Einfolk inside a treasure box within Hall, one of the Ruins of the Ymir Theocracy. Stiyl adopted her into the Einfolk family, raising her as his daughter.

Seven years before the main events, Krulcifer was taken by several nobles to Hall during the annual Pilgrimage Festival in an attempt to unlock the Ruin’s secrets. Their actions caused Hall to rampage and release a number of Abyss, which the Drag-Knights of the time struggled to suppress.

Krulcifer devoted herself to excelling in various fields in hopes of being accepted by her adoptive family. However, her efforts only created greater distance between them. During a tournament two years prior to the story, she defeated Mel Gizalut and was awarded the Divine Drag-Ride Fafnir. This victory, however, cast shame on her adoptive brother Zain Einfolk, who had previously been defeated by Mel, damaging his reputation and subjecting him to hardship.

About a year and a half before the present timeline, Krulcifer was once again taken to Hall by church officials, triggering another rampage. Trapped beneath rubble, she was rescued by Stiyl, who sustained severe injuries in the process. Left unable to fight and reliant on a cane, Stiyl chose to distance Krulcifer from the Einfolk family to shield her from further exploitation.

Following these events, Krulcifer traveled to the New Kingdom of Atismata and enrolled in the Royal Officer Academy, where she continued her studies and training as a Drag-Knight.

Krulcifer is depicted as a refined and elegant young woman with waist-length blue hair, often adorned with a black ribbon, and striking blue eyes that carry a cool, distant glow. She has a slender figure and is frequently noted for her beauty and poise. Lux Arcadia once described her as resembling a flawless work of art, with a graceful presence that conveys both maturity and composure.

Krulcifer is portrayed as composed, witty, and self-assured, often recovering quickly from moments of embarrassment with clever remarks. She has a straightforward and daring nature, preferring to confront challenges directly and relying on herself to resolve personal problems. This independence, however, sometimes leads her to undervalue her own worth, such as when she downplays her abilities after receiving Lux Arcadia’s help in a duel. She also enjoys teasing others and has shown a playful, sometimes manipulative side, though her overall demeanor remains grounded and pragmatic.

While she maintains an air of composure, Krulcifer is sensitive about her small chest size. Although she rarely overreacts, she openly shows annoyance when the subject is brought up, once even threatening La Krusche after the Automaton suggested methods to increase it.

Beneath her cool and confident exterior, Krulcifer deeply values how others perceive her. Having been discovered as a child within a Ruin, she worked tirelessly to earn acceptance from the Einfolk family, striving for recognition and belonging. Similarly, after falling in love with Lux, she constantly seeks to present her best self in hopes that he will reciprocate her feelings. Despite this, she is not possessive; she acknowledges and even accepts the presence of rivals who share affection for Lux, reflecting both her confidence and her maturity in matters of love.

Krulcifer is regarded as one of the strongest Drag-Knights of the Ymir Theocracy and has demonstrated the ability to fight on equal terms with members of the Seven Dragon Paladins when necessary.

• Authority over Ruins: As an Xfer, Krulcifer possesses limited control over Ruins, enabling her to open doors and manage certain functions within them. This power, however, comes with restrictions; opening particularly important doors temporarily prevents her from doing so at other Ruins.
• High Drag-Ride Aptitude: Her status as an Xfer grants her a higher affinity with Drag-Rides than ordinary humans, enhancing her combat capability.
• Martial Arts: Outside of Drag-Rides, Krulcifer is skilled in hand-to-hand combat, capable of subduing opponents with swift, efficient throws. She has even managed to throw Lux, despite his own advanced combat training.
• Marksmanship: Krulcifer excels in high-speed precision shooting, able to target and strike opponents’ weak points with exceptional accuracy.
• Full Connect: As an Xfer, Krulcifer can access Full Connect, a unique state in which she fuses with her Drag-Ride. This ability drastically increases her reaction speed by linking her nervous system with the Drag-Ride’s sensors, granting her superior precision and manual control over its special armaments. However, in this state she also experiences the pain of damage inflicted on the Drag-Ride.
• Baptism: At the order of Queen Raffi, Krulcifer underwent Baptism, which enhanced her ability to maintain and stabilize the Full Connect state.

Fafnir
Krulcifer’s Divine Drag-Ride is Fafnir, a well-balanced model noted for its versatility in offense, defense, and mobility.

• Freezing Cannon (凍息投射, Furījingu Kanon, lit. Freeze Projection): Fafnir’s primary special armament, a long-range sniper weapon that fires freezing projectiles. The generated ice is durable enough to restrain powerful Abyss such as Golems. Krulcifer’s accuracy with the weapon makes her attacks difficult to evade, though its freezing effect can be negated if the shots are intercepted or blocked by external objects.

Lux Arcadia
Krulcifer develops romantic feelings for Lux, initially sparked when he helped her escape an unwanted engagement and later supported her in reconciling with her adoptive family. She admits to being attracted to his decisive side, though she frequently teases him about his youthful face and short stature.
Their relationship evolves gradually. During their first meeting, Krulcifer mistook Lux for a pervert and subdued him despite finding him attractive. Over time, she began confiding in him, revealing her desire to uncover the truth about the Black Hero. When Lux revealed his identity, she agreed to support him in battle.
To avoid being pressured into another engagement, Krulcifer asked Lux to act as her boyfriend. Initially, her feelings were not serious, but after sharing their pasts with one another, her interest deepened. She also supports him academically, serving as his private tutor due to his lack of formal study experience.

Lisesharte Atismata
Krulcifer and Lisesharte are rivals in love but also close companions. Although their relationship began with tension due to their mutual affection for Lux, it developed into one of respect and friendship. In the light novel, the two were forced to cooperate in a tournament against Celis Ralgris. Though they lost, the experience strengthened their bond, leading them to acknowledge each other as both comrades and rivals. They later confide in one another and share discussions about personal matters, highlighting the trust that grew between them.

Stiyl Einfolk
Stiyl Einfolk discovered Krulcifer as a child in the Ruin of Hall and adopted her into the Einfolk family. Although she initially felt unloved by her foster family, she later learned that Stiyl had intentionally distanced himself to shield her from political factions in Ymir who sought to use her as a key to the Ruins. He also revealed that her study abroad in the New Kingdom had been arranged to protect her rather than to find a fiancé, and that he had saved her during a Ruin rampage a year and a half before the present. With this truth revealed, Krulcifer was finally able to accept her place within the Einfolk family.