Tsukihi Araragi is a notable character from the Monogatari Series, known for her vibrant personality and dynamic role in the story. As the younger sister of protagonist Koyomi Araragi, Tsukihi is part of the Araragi family, which plays a central role in the series. She is characterized by her fiery temperament and strong-willed nature. Despite her human appearance, Tsukihi is revealed to have supernatural origins, being a 'phoenix' or 'immortal bird'. Her character brings both comedic and dramatic elements to the series, often serving as a catalyst for key plot developments.