Upon her initial release from the seal within Rem Galleu during the Demon King Revival Ceremony, Krebskulm emerged in a form befitting her title as the Demon Lord of the Soul. Her original form was that of a towering humanoid creature, approximately three meters in height, dwarfing even the tall Diablo, who only reached her waist. Her body featured a long, narrow, snake-like torso with a glossy black surface reminiscent of insect armor. Her head bore two curved horns and five glowing red eyes two on each side and one in the center. From her back extended giant, radiant wings of light, enhancing the sinister and divine quality of her presence. This fearsome form projected overwhelming power and terror.

However, shortly after her release, Krebskulm’s body mysteriously transformed into that of a young girl, drastically reducing in size and appearance. In this new form, she appeared even smaller than Rem, with a cute, animal-like charm. She retained curved goat-like horns on either side of her head, and her elf-like ears, amethyst-purple eyes, and blonde cream-colored hair tied in twin tufts reaching down to her knees added to her youthful and innocent look. A lizard-like tail extended from just above her waist. Her outfit consisted of a frilly dress with openings that exposed her shoulders and stomach, further accentuating her childlike yet non-human features.

To avoid suspicion while entering Faltra City, Krebskulm initially disguised herself by wearing Alicia’s mantle, which covered her horns and tail, allowing her to pass as a demi-human. Later, when Mei, the shopkeeper, discovered that both she and Edelgard were Fallen, she offered to help conceal their identities. Under Mei’s guidance, Krebskulm was dressed in an idol-like costume. Her naturally translucent skin required no foundation, so Mei applied eyeshadow and eyeliner to enhance her features. Her horns were disguised as decorative accessories beneath a stylish hat, and her tail was hidden beneath a parasol-shaped skirt, completing her disguise.

Despite her fearsome reputation as the Demon Lord of the Soul, Krebskulm particularly in her childlike form displays a personality that is surprisingly gentle, cheerful, and innocent. She behaves much like a sweet-natured child, showing kindness and warmth toward those around her, provided she is not provoked or threatened.

She generally adheres to a “live and let live” attitude and demonstrates a friendly disposition, although her temperament occasionally shifts in comedic or impatient moments where she might lightheartedly express a desire to incinerate people en masse, often more as a reflection of immaturity than malice.

Though Krebskulm harbors great destructive potential, her nature is not inherently violent. In fact, she is shown to be capable of learning, adapting, and even restraining herself over time. When in her berserker mode, triggered by extreme emotional states or threats, she becomes unable to distinguish between friend and foe. However, even in this state, she is not entirely mindless. Krebskulm retains a degree of awareness, and as the story progresses, she demonstrates the ability to learn from her experiences and manage her impulses with guidance.

Her character ultimately contrasts with the dark legend that surrounds her presenting a nuanced depiction of a being feared as a Demon Lord, yet capable of warmth, growth, and companionship.

Krebskulm, known as the Demon Lord of the Soul, was once part of a single unified existence shared among the Demon Lords, beings of immense power who opposed the divine order. However, after their defeat by God, Krebskulm was split from the others, becoming an independent entity embodying the soul of their collective being.

Following her separation, Krebskulm was sealed away to prevent her resurrection and the potential return of demonic chaos. The seal was placed within a member of the Galleu bloodline, beginning a generational curse. The first vessel was one of Rem Galleu’s ancestors, and since then, the Demon Lord’s soul has been passed down maternally, from mother to daughter, eventually residing within Rem herself.

This curse shaped Rem’s life and motivations, as she grew up aware that her death would trigger the full revival of Krebskulm. Krebskulm’s eventual release from Rem’s body becomes a pivotal turning point in the story, transforming the feared Demon Lord into a surprisingly childlike and complex figure.

Krebskulm possesses an immense and overwhelming degree of magical power. Diablo, one of the most powerful magic users in the series, describes her magic as being so vast that it is difficult to comprehend. Unlike ordinary magicians who store magical energy within their bodies, Krebskulm’s power appears to flow like a river endless and uncontainable suggesting she draws from a source of near-limitless magical energy. This makes her one of the most formidable beings in existence from a purely magical standpoint.

However, upon her initial release in the form of a child, Krebskulm had no memory of the advanced spells she once knew as a fully awakened Demon Lord. In this regressed form, her abilities were limited to casting basic magical blasts and enhancing the strength of nearby Fallen by bestowing her magical power upon them. Even so, these simple attacks were exceptionally powerful due to the sheer quantity of magic she could channel.

Later in the story, after experiencing the trauma of witnessing what she believed to be Rem’s death, Krebskulm momentarily returns to her true form. With this transformation, her full magical potential is reawakened, and she regains knowledge of more advanced abilities. These include infusing her fists with magical power to increase the strength of her physical attacks, unleashing destructive area-of-effect techniques such as a breath attack, and casting high-tier magic resembling the spell (Lightning Meteor). Her combat abilities in this state are devastating, capable of overwhelming even elite opponents.

In addition to her magical prowess, Krebskulm also demonstrates tremendous physical strength. She is shown to be capable of lifting and throwing massive objects, including coffins and pieces of fortress ramparts, using them as improvised weapons against her enemies. Finally, she exhibits a mysterious power linked to soul manipulation: she can transform fallen bodies into bell-shaped objects before they vanish into light, suggesting a limited but potent ability related to resurrection or spiritual preservation.