The protagonist of this work. An Earthling. He was scouted by the Galaxy Federation Police as a space detective candidate, and became a trainee, eventually becoming a space detective. "Shaider" is his code name, derived from the legendary hero and warrior Shaider.
When Sawamura Dai issues the code "sintering", plasma blue energy is emitted from the mother ship, the Babylos, and the special light alloy Granium α combat suit that is constructed from this is sintered into Shaider. The sintering process takes only 1 millisecond (1/1000 of a second), just like Sharivan. Small, high-performance servo computers are placed in both arms and legs to support Dai, who has little combat experience. The dimension controller on his chest allows him to operate in other dimensions and outer space. If the code cannot be recognized by voice, Annie can manually activate the sintering.