Fern has a mature personality as a result of her upbringing, leading her to often act as the mother of the party. She constantly has to help Frieren perform ordinary tasks such as waking her up due to her being a deep sleeper, feeding her, and dressing her, along with cleaning up her messes. She acts similarly around Stark, such as getting mad when he stays up late, even though they are around the same age. Despite her outward motherly nature, Fern is easily upset and can act childish when others don't cater to what she wants or offend her, and in extreme cases, pouting and completely ignoring them when they attempt to reconcile, though this can be resolved through actions like treating her with food and abiding by demands she makes. Fern is also a very loyal apprentice and has the discipline to train incredibly hard since she was young so she can manage on her own, ultimately becoming a powerful mage acknowledged by Frieren. Fern is a young human with purple eyes and long, waist-length purple hair with bangs. She usually wears her hair down with two additional chest-length strands framing her face in a hime-style haircut and partially tied back. After turning sixteen, Fern grew to be taller than Frieren and with a more developed figure. As a result of her mature and calm personality, she frequently wears a stoic expression and rarely expresses strong emotions. Her facial features are characteristic of those from the Southern Lands. For Fern's sixteenth birthday, Frieren gifted her a butterfly hair ornament, which Fern regularly wears on the back of her head to partially tie her hair back.[7] Fern also frequently wears a mirrored-lotus bracelet on her left wrist, gifted to her by Stark for her eighteenth birthday. As a mage, Fern wields a long, wooden staff wrapped with purple ribbons in battle, which was a gift to her from Heiter.

Frieren has an easy-going personality, but her aloofness leaves her a mystery to her peers, as humans and elves usually have different views on life. As an elf who has lived for at least a millennium, Frieren has a different sense of time, as reflected by her unchanging habit of lying in bed until very late in the morning, and her deeper inability to grasp the speed at which time passes for humans. Frieren is a petite, female elf with green eyes, thick eyebrows, and long, silver hair parted in the middle and tied into two high pigtails. Like all elves, she has large, pointed ears. When casting spells as a mage, Frieren utilizes a red staff with a gold, crescent-shaped tip that holds a red jeweled orb in its center. Her staff has gold accents and a red ribbon tied at the tip.