Kuguru Uki, a sixth-year elementary student at Aibo Academy and classmate of Gao Mikado, is also the childhood friend of Baku Omori. Her appearance is marked by purple hair styled in two small pigtails that emerge from circular lamps on her head, capable of lighting up, and red-framed glasses. She typically wears a white long-sleeved sailor shirt featuring a fuchsia ribbon and teal accents that extend into a skirt-like design, paired with thigh-high white boots matching the teal trim. Renowned as "The Library" for her encyclopedic knowledge of Buddyfight cards, she constantly utilizes a tablet to display card data during analysis. This expertise defines her position as the primary card analyst and strategist for Team Balle du Soleil. She provides essential tactical support during matches and offers emotional encouragement to teammates Gao Mikado, Baku Omori, Kiri Hyoryu, and Tetsuya Kurodake. Her contributions involve crucial deck-building assistance and situational advice during fights. Demonstrating strong loyalty and protectiveness, she blackmailed Baku into constructing Gao's deck and physically intervened when Baku dismissed emotional sentiments. She harbors a recurring crush on Baku, hugging him after Gao's victories and reacting visibly to his comments about prioritizing food over relationships, including moments like stuffing bananas into his mouth following such dismissals. She carries cat toys and shows open affection towards feline Buddy monsters like Cait Sith, often seen brushing or fawning over them. Primarily a non-combatant support figure, she rarely participates in Buddyfights herself. Her documented fight record includes a victory against Baku disguised as Shusui Kanahebi and a loss to Zanya Kisaragi. Her role lessens in later seasons like Hundred and X as the narrative focus shifts to new characters; she appears sporadically, maintaining her supportive function without significant development or expanded backstory in spin-offs or movies. A cameo features her with friends on a television screen in Cardfight!! Vanguard Movie: Neon Messiah. She displays antagonism toward Ozon-B, threatening violence such as using chainsaws to drive him away. Her inclusion as a character in All-Star Fight is documented, with no further official details regarding her involvement or expansions on her background or development in other media.