Byleri is an archer and adventurer from the Crylord Magic Kingdom who becomes a companion of the protagonist, Flio. Her background is notably humble for a member of a knightly party, as she originally worked as a caretaker for warhorses in a castle's stables and was never formally trained as a warrior. Despite her lack of combat experience, she eventually joined a knight order as a bow user, becoming a member of the same party as Balirossa, Blossom, and Belano. This group later came to live with Flio after he saved their lives and they decided to follow him.

Personality-wise, Byleri is defined by her profound kindness and gentle nature, which is most clearly expressed in her extraordinary love for animals. This compassion, while a virtue, becomes a significant drawback in her role as a fighter. She finds it genuinely difficult to fight monsters or any living target, often hesitating to attack if she feels sympathy for her enemy. This sensitivity makes her the weakest combatant in her party, as her caring nature can be a liability in battle. Despite this, she is earnest and tries her best to support her companions.

Her primary motivation is not martial glory but a pastoral dream: to start a business transporting goods with horse-drawn wagons. This ambition stems from her true talent and passion for animal care. She aspires to own a large piece of land where she can care for both ordinary animals and magical beasts. This desire directly influences her role in the story, as she asks Flio for more land to expand their homestead for agricultural and animal-breeding purposes. After the party moves to the village of Houtau to live together under Flio's roof, she takes the initiative to set up a pasture next to their farm to raise horses and cows, contributing to the household's income.

Byleri's key relationships are primarily with her fellow party members and Flio. She is close with Balirossa, Blossom, and Belano, having worked alongside them as a unit before their association with Flio. Her relationship with Flio is built on gratitude and trust, as he acts as a patron who supports her dreams by agreeing to help expand their land for her animal projects. She also has a notable dynamic with the powerful wolf warrior Rys; Byleri prefers to shoot at stationary targets, while Rys pushes her to fight moving monsters to improve her archery skills, leading to occasional arguments.

Throughout the narrative, Byleri undergoes significant development that redirects her from a struggling warrior to a skilled tamer. Initially, her combat arrows are shown to be ineffective, even bouncing off the skin of a Psychobear. However, her innate talent with animals becomes her true strength. This is dramatically illustrated when she single-handedly calms a rampaging, horse-shaped magical beast by crafting makeshift reins and soothing the creature, proving her abilities far exceed those of an average fighter. Her arc shifts from trying to fulfill a knight's duty to embracing her vocation as an animal caretaker and tamer. Later developments also place her in more domestic scenarios; at one point, she is among the housemates who become bedridden with a mysterious ailment and cravings for lemons, hinting at upcoming family additions in the household.

Regarding her notable abilities, Byleri is officially classified as an archer, though her combat skills are only average due to her reluctance to fight. Her true expertise lies in animal care and taming. She is exceptionally skilled at handling horses and can even calm down magical beasts, using nothing but homemade reins crafted from whatever materials are at hand. She is capable of promptly dealing with animal-related issues, such as when a monster invades a farm. Physically, Byleri is an adult female with short, red-brown or brown hair that falls to about her ears, and orange eyes. She typically wears light, practical armor suitable for an archer, with green as a predominant color in her outfit.