Tsukihi is a young girl in her early teens, with black hair and dark gray eyes. She wears a sunny-side-up egg-shaped hair clip on the left side of her hair, a detail that mirrors her older sister Karen, who wears hers on the opposite side. Like the other Araragi siblings, Tsukihi has a distinctive ahoge that adds expressiveness to her appearance.

She is known for frequently changing her hairstyle, often appearing with different looks throughout the series. Her clothing style primarily features bright-colored yukatas and kimonos of varying lengths, giving her a vibrant and traditional aesthetic.

Compared to her older sister Karen, Tsukihi prefers indoor activities and a more reserved lifestyle. Despite her calm outward appearance, she has a notably short temper, with Koyomi describing her as prone to bouts of hysteria. Tsukihi is romantically involved with Rosokuzawa, a relationship she claims is chaste, though she openly expresses that she is in love with him.

As a member of the Fire Sisters, Tsukihi supports the group’s ideals of justice but admits that she lacks the same intense motivation that drives Karen. While she shares the family’s strong belief in standing up for what is right, she often displays a more airheaded and carefree attitude.

Ironically, despite her true nature as an oddity, Tsukihi, like her sister, dismisses the existence of the supernatural, remaining unaware of her own origins.

Tsukihi Araragi is the youngest child in the Araragi family, growing up alongside her older siblings, Koyomi and Karen. Although raised in an ordinary human household, Tsukihi is unknowingly an aberration, the offspring of the Shide no Tori, a supernatural being with phoenix-like attributes. This grants her extraordinary regenerative abilities, making her effectively immortal despite her human appearance.

Throughout her upbringing, Tsukihi remained unaware of her true nature, believing herself to be an ordinary girl. Together with Karen, she formed the “Fire Sisters,” a self-styled vigilante duo committed to promoting justice at Tsuganoki Second Junior High School. While Karen often takes a more aggressive approach to their activities, Tsukihi’s involvement is more passive, though she shares her siblings’ general belief in protecting others.

Her life continues largely unaffected until the events of Tsukihi Phoenix in Nisemonogatari, where her true origins come into focus, forcing those around her, particularly Koyomi, to confront the complexities of identity and authenticity.

Koyomi Araragi
Tsukihi shares a close and sometimes combative sibling relationship with her older brother, Koyomi. Although they frequently bicker and tease one another, Tsukihi cares deeply for him, and Koyomi is protective of her in return. Their bond is marked by a mix of playful conflict and genuine familial affection.

Karen Araragi
As the younger half of the Fire Sisters duo, Tsukihi works alongside Karen to uphold their shared ideals of justice. While Karen is energetic and physically active, Tsukihi provides a calmer, if somewhat less motivated, counterpart. Despite their differences in personality and approach, the two sisters maintain a strong, supportive relationship.

Rosokuzawa
Tsukihi is romantically involved with Rosokuzawa, as mentioned by Koyomi. She openly admits to being in love with him, though she insists their relationship remains chaste.