Eishirō Sugata serves as president of Sorami High School's New World Discovery Club, researching the mysterious "New World" phenomenon in the city's sky. He maintains a consistently calm and analytical demeanor, rarely displaying overt emotion. Tall with light gray hair and blue-green eyes, he wears only his school uniform and large rectangular glasses due to possessing no other clothing.

His background involves a prominent political family and profound tragedy when his older brother died during a glider test flight. Sugata blamed himself for inadequate inspection after an argument, resulting in disownment and leaving his younger brother Yuugo as heir. Seeking atonement, he dedicated himself to discovering the "New World" to honor his brother's passion for exploration and flight. He resides in a riverside tent, embodying survivalist and explorer principles.

In *The Angeloid of Clockwork*, Sugata greets Hiyori Kazane's club membership attempt with skepticism, recalling an angel resembling her in Synapse. He opposes her joining until Mikako Satsukitane mentions the budget increase from new members. As Hiyori bonds with Tomoki, Sugata investigates her Synapse connection, questioning Daedalus about her resemblance to an angel and linking it to Tomoki's memory lapses. After Hiyori's death and erasure from memory, Sugata races to Synapse but fails to recognize her in the pod, enduring taunts from the Master of Synapse about forgotten memories. During the climax, he assists Tomoki and the Angeloids against the transformed Hiyori, countering her time-manipulation abilities with tactical support.

Across other media, Sugata researches Angeloids and Synapse, collaborating with Daedalus to uncover its secrets and impressing the Master of Synapse with his intellect. In the manga, he infiltrates Synapse to reprogram the Rule Obelisk, seemingly sacrificing himself before restoration via Tomoki's wish. The spin-off *Yūryō Bukken Mō Dame Sō* confirms his brother Yuugo recognizes their familial tie; Sugata contacts him to discuss the "New World," revealing his awareness of Synapse's nature. Another spin-off features Mikako organizing an impromptu birthday celebration with him, highlighting their enduring connection despite his typically reserved nature.

Sugata employs a scientific approach to analyze Angeloid capabilities and artifacts like Ikaros' Transport Cards. He provides exposition at anime episode openings, using historical explorers as metaphors for the club's discoveries. His combat skills equal Mikako's, and he demonstrates resourcefulness in field operations, such as using a bicycle to reach observation sites during emergencies.