Ryū Zaō is a second-year Binan High School student affiliated with the Earth Defense Club. His given name carries the meaning "standing" (立), featuring an atypical reading for the kanji addressed in audio dramas. His surname Zaō, signifying "warehouse, cellar" (蔵) and "king, prince" (王), connects to a famed snowboarding and onsen resort in Yamagata Prefecture. Physically, Ryū sports pink hair held by a white headband, featuring spiked hair at the back and a loose strand on his left forehead. His brown eyes complement his 177 cm height and blood type B. He uniquely wears two ear piercings on each ear among the club members. His standard uniform consists of black pants, an untucked white shirt, an unbuttoned black blazer, a red tie, and brown shoes. Transforming into "Thrilling Prince, Battle Lover Vesta" (トキメキ王子バトラヴァ・ヴェスタ) outfits him in a prince-styled ensemble with pink accents, including a heart-shaped jeweled bow, white gloves, shorts with pink borders, and pink boots. His personality is playful and jovial, emphasizing camaraderie within the Earth Defense Club. He champions the motto "Women are life!" and openly expresses admiration for girls, listing them alongside cherries as his likes. Interactions with his close friend Io Naruko, however, suggest complexities in his feelings. Episode 7 implies Ryū may not genuinely prefer women, potentially harboring a crush on Io. During Season 2 Episode 9, while receiving numerous Valentine's chocolates from girls, he presents a personal box to Io, who accepts it with a blush; Ryū later claims he will receive more chocolates than Io by day's end. Ryū wields fire-element abilities. His transformation weapon is the "Blazing Ignit," enabling the "Vesta Ignit" attack. He shares a strong bond with classmate and fellow second-year Io Naruko, who is implied to reciprocate romantic feelings. Conversely, his relationship with Conquest Club member Akoya Gero is strained. Background details include an unnamed stepsister within his family. His hobbies encompass snowboarding, aligning with his surname's origin. Trivia reveals he is notably ticklish.