Takuya Kai (甲斐 拓也 Kai Takuya?)/Blue Beet (ブルービート Burū Bīto?) is a 23-year-old entomologist at the Earth Academia Japan Branch and is the team leader. He is very tender-hearted. His sense of responsibility is very strong. The first to meet Guru in the South American rainforest, he was also the first to gain a B-Commander and use his suit. As Blue Beet, his armor was modeled after a male Japanese rhinoceros beetle. His blood was used in the creation of his "evil twin", Shadow. After learning the true colors of the shadow, he feels responsible and goes missing. In the second half of the series, Blue Beet gained the ability to evolve into Super Blue Beet (スーパーブルービート Sūpā Burū Bīto?) by the command "Metal-Phose!" (重甲超進化（メタルフォーゼ） Metarufōze?).