Ryuichi Takeshima progressed from Esperion Junior Youth to the Tokyo City Esperion Youth academy as a center-back. His defensive strengths stand out within Esperion's typically attack-focused soccer philosophy. He possesses distinctive red hair styled in a pompadour and red eyes, matching a confident, flamboyant personality suggestive of a playboy persona. His blood type is O and his zodiac sign is Libra. A younger version of him exists, though specific childhood details remain unspecified. Takeshima excels defensively through an exceptional sense for maintaining optimal distance between himself and opposing attackers. This skill allows him to accurately gauge opponent speed and apply disruptive pressure at precise moments during matches. He maintains a close friendship with fellow player Yūma Motoki. His interactions with Eisaku Ōtomo are strained, however, as Ōtomo harbors a one-sided grudge stemming from Takeshima frequently bringing him to the ground during play. Takeshima also engages in an ongoing feud with Keiji Togashi, alongside Kanpei Kuroda, arising from fundamental differences in their soccer approaches and philosophies. His name derives from Japanese elements: "Ryū" (龍) meaning "dragon," "Ichi" (一) meaning "first," "Take" (竹) meaning "bamboo," and "Shima" (島) meaning "island."