TV-Series
Description
Fatla is a supporting character in the anime series Ive Been Killing Slimes for 300 Years and Maxed Out My Level. She serves as the personal secretary to Beelzebub, a high-ranking demon and minister in the Demon Kingdom. Fatla herself is a member of the Leviathan race, a type of demon known for its immense size and power.

True to her Leviathan nature, Fatla possesses two primary forms. In her human form, she appears as a tall young woman with a slender yet curvaceous build. She has long, straight blue hair that flows down to her waist, with bangs that often cover her right eye, and her eyes are also blue. Distinctive fin-like protrusions are visible on her head, marking her as a demon. When she transforms, she reveals her true shape, that of a colossal, whale-like flying creature so massive she is described as resembling a ship, with multiple buildings resting on her back. In this form, she is used for long-distance travel in her role as a sort of living transport for important guests.

Fatla is characterized by her calm, serious, and highly efficient demeanor. Among the acquaintances of the protagonist Azusa, Fatla is considered one of the most responsible and formal individuals. She performs her secretarial duties flawlessly and with great dedication, earning praise from her superior, Beelzebub. Despite her professional exterior, Fatla has a few notable quirks. She has a strong fondness for moss, going so far as to decorate her office with it, a practice that once led to mold growth due to the humidity. She also enjoys moss baths, where she immerses herself completely in moss for relaxation. Additionally, while she denies it, she is said to have a secret liking for a dish called La-Ment, which appears to be a version of ramen in her world.

Fatla is the older twin sister of Vania, another Leviathan demon. Her relationship with her younger sister is a key part of her character. Fatla is constantly concerned for Vania's well-being and acts as the more responsible of the two. However, Vania's carefree and sometimes clumsy nature frequently tests Fatla's patience. In one instance, while Vania was piloting her Leviathan form, she remembered a funny joke and began to laugh uncontrollably, causing the giant creature to shake violently. This resulted in Fatla, who was acting as a guide, spilling her tray of drinks and falling over. This incident led to a very uncharacteristic outburst of frustration from the usually composed secretary, demonstrating that her serious nature has its limits when it comes to her sister.

Her primary role in the story is tied to her position as Beelzebub's assistant in the Ministry of Agriculture. In this capacity, she helps facilitate travel to the Demon Kingdom and acts as a guide and attendant for Azusa and her family. Her relationship with Beelzebub has seen some development over time. According to spin-off material, when Beelzebub was first and suddenly promoted to minister, Fatla was suspicious of her new superior's abilities and initially acted as though she was monitoring her. However, after witnessing Beelzebub's dedication and hard work, Fatla came to recognize her competence and became a loyal and supportive subordinate.

In terms of abilities, Fatla's most notable power is her transformation into a gigantic flying Leviathan, which serves as a practical method of mass transport. In her human form, no specific combat or magical abilities are highlighted, as her primary function is administrative and logistical. Her overall character development is subtle, focused mainly on her evolving trust and respect for Beelzebub and her ongoing, slightly exasperated but loving relationship with her younger twin sister, Vania.