Ryū Zaō is a second-year student at Binan High School and a core member of the Earth Defense Club. He sports distinctive pink hair styled backward with a white headband, brown eyes, two piercings on each ear, and stands 177 cm tall. His school uniform—black pants, unbuttoned black blazer, white shirt, red tie, and brown shoes—is often worn with a casually rebellious flair.

He transforms into the Thrilling Prince, Battle Lover Vesta, donning a prince-inspired costume featuring pink and white details, puffed sleeves, coat tails, a heart-shaped jewel, white shorts, and pink boots. His elemental attribute is fire, symbolized by the color pink. His primary weapon is the "Love Stick," channeling pink flames for attacks like the Season 1 "Vesta Ignite" and the upgraded Season 2 "Vesta Love Ignite." His transformation activates with the phrase "Love Making!" triggered by a kiss to his bracelet.

Ryū displays a jovial, playful personality, frequently declaring "Women are life!" as his motto. Though no female characters appear, prompting speculation among peers about his sincerity, he enjoys popularity with younger students who see him as a protective "big brother." Academically below average, he deeply values friendships, especially with his classmate and best friend Io Naruko. Their dynamic includes casual nicknames ("Ryū" and "Io"), frequent collaboration, and occasional arguments—such as a Season 2 conflict that briefly disrupted their teamwork during a monster battle. They reconciled quickly, however, executing a joint attack to defeat their foe.

He maintains a competitive relationship with Akoya Gero, partly fueled by their rivalry in a "Handsome Contest." Ryū enjoys snowboarding and cherries but dislikes konjac and "breakup talks." Trivia notes reveal he is ticklish and recall a Valentine’s Day episode where he exchanged chocolates with Io, hinting at underlying mutual affection. He remains active in the Defense Club in the *Eternal Love!* movie (2025).