Hestia is a goddess who presides over the Hestia Familia in the labyrinth city of Orario. She is a divine being who descended from Heaven, where she was known as one of the three great virgin goddesses. In the lower world, her appearance is that of a petite and beautiful young woman with a youthful face, round blue eyes, and long black hair that reaches past her hips, usually styled into two twin tails with distinctive white and blue ribbon ornaments. Despite her small stature, standing at approximately 140 centimeters or 4 feet 7 inches tall, she has a mature figure, which has led to her being humorously nicknamed the Loli Big-boobs by other deities. Her typical attire consists of a revealing white mini-dress held up by a blue ribbon tied around her chest and under her arms, paired with white gloves, and she is most often barefoot.

Personality-wise, Hestia is generally an energetic, kind, and cheerful goddess who speaks in a direct and friendly manner. She is known for being hardworking, taking on multiple jobs, including working for the Guild as a clerk and at food stalls, to support her familia and pay off debts. However, she can also display a lazy and somewhat clumsy side, as seen when she initially lived off her friend Hephaestus before being asked to become more independent. Her most defining personality trait is her deep, romantic affection for Bell Cranel, the first and only member of her familia for a considerable time. This love makes her intensely jealous and possessive, viewing any girl who gets close to Bell as a rival, particularly Ais Wallenstein, whom she often refuses to name directly, calling her instead by dismissive epithets. She is also fiercely protective of Bell, worrying constantly about his safety and well-being whenever he enters the Dungeon.

Hestia's primary motivation is to nurture and protect her familia, with Bell as its cornerstone. She dreams of one day being in a romantic relationship with him, and much of her actions are driven by a desire to support his growth and keep him close. This is most evident when she commissions the Hestia Knife, a powerful and unique weapon for Bell, accruing a massive debt of 200 million valis that she works tirelessly to repay. She is also deeply motivated by pride in her familia and a desire to see it flourish, moving them from their initial home in an abandoned church basement to the far grander former estate of the Apollo Familia after a victorious War Game. Furthermore, she is wary of the dangers that Bell's unique and rapid growth could attract, leading her to initially conceal the existence of his special skill, Realis Phrase, from him and others to protect him.

In the story, Hestia serves as Bell's patron deity and the emotional anchor for her familia. Her role involves granting and updating her familia members' statuses, a process known as the Falna, which allows them to grow and become stronger adventurers. She also acts as the group's leader and decision-maker, albeit one often swayed by her personal feelings. Her relationships with other characters are key to her role. With Bell Cranel, she shares the closest and most complex bond; he is her beloved first follower, and despite his obliviousness to her romantic advances, she is his most dedicated supporter. Her relationship with the goddess Hephaestus is one of a close, supportive friendship, built on the fact that Hestia never mocked her for her disfigurement. In contrast, her dynamic with Loki, the leader of the powerful Loki Familia, is a rivalry of verbal insults, often centered on Hestia mocking Loki's flat chest and Loki mocking Hestia's small familia. She also maintains friendships with other deities of smaller familias, such as Miach and Takemikazuchi.

Hestia undergoes notable development throughout the series. Initially a lonely goddess unable to recruit any followers, she evolves into the proud and capable head of a growing familia, gaining new members like Lili, Welf, Mikoto, and Haruhime. Her love for Bell matures from simple jealousy to a more profound, sacrificial dedication, as seen when she takes on a life-changing debt for his sake. A significant moment of development occurs in the fifth season when she demonstrates her divine power on a grand scale. To counteract Freya's immense charm that had enslaved the entire city and stolen Bell away, Hestia invokes her sacred flame, Aedes Vesta, successfully purifying Orario and breaking the spell, proving that the bonds of the hearth and a true home are more powerful than forced adoration.

As a goddess, Hestia possesses notable abilities, though she is forbidden from using her full divine power in the lower world. However, in moments of extreme crisis, she can channel her authority over the eternal flame, which allows her to perform powerful acts like the Purification Flame that cleansed Freya's charm from an entire city. She is also inherently highly resistant to divine charms, making her one of the few beings who can stand against the influence of a goddess like Freya. Her primary functional ability in daily life is granting and managing the Falna, which unlocks the potential for heroic growth in her followers.