Lala's gift to Rito for his 16th birthday, Celine is a multi-tiered, carnivorous, sentient sunflower residing in the backyard of the Yuuki household. Despite her monstrous appearance, Rito cherishes Celine deeply, considering her part of his family. The plant exhibits human-like behaviors: sweating in humid weather, wearing an oversized scarf on chilly days, and even enjoying a bowl of ramen when hungry (though she still requires water and sunlight). When Celine falls ill with a deadly disease, Rito dedicates himself entirely to saving her from Kare Kare by searching for the luckyberry. Alongside his friends, they embark on a perilous journey to the S-level-danger planet Misletoe to find an antidote. Upon their return, they discover Celine seemingly dried up, only to realize she was germinating. From her single seed emerges a baby girl with a flower atop her head—Celine reborn.
This transformation astonishes even Momo, who is well-versed in galactic flora, as she admits that Celine's biological composition remains a mystery. Referring to Rito as her "mama," the infant Celine develops an intolerance for cola and can release pollen from the flower on her head, causing anyone who inhales it to temporarily fall in love with Rito—a side effect stemming from her affection for him due to his daily care. As a child, Celine has a playful habit of tackling girls and attempting to breastfeed from them, leading to comedic misunderstandings where she is mistaken for Rito's daughter. Both as a plant and an infant, Celine makes appearances in the animated adaptation.
