Naoto Ijūin is a seventeen-year-old member of the Crasher Squad, the elite Earth defense unit that operates under Commander Ōtsuka. He serves as the weapons operator for the squad’s large space fighter, the Cosmo Crusher. In the early part of the story, Naoto is openly hostile toward the protagonist, Takeru Myōjin. He does not trust Takeru because of Takeru’s secret identity as an alien from the planet Gishin, and he frequently picks arguments with him. Despite his abrasive and sarcastic manner, Naoto has a strong sense of loyalty to his comrades and a genuine desire to protect Earth. Over time, he becomes impressed by Takeru’s selfless dedication to defending others, and the two develop a solid friendship based on mutual respect. As the series progresses, especially during the Earth arc, Naoto takes on a larger role as the main pilot of the Cosmo Crusher when the squad leader, Kenji Asuka, is increasingly deployed elsewhere. Naoto’s character is defined by his initial suspicion and defensiveness, which gradually give way to trust and camaraderie. He is a skilled pilot and gunner, and his bravery grows alongside his deepening commitment to the team and to Takeru. His character design was originally a rejected concept sketch for Takeru, and he remains a steadfast ally through the various conflicts with the Gishin Empire, the Marmelo system, and the final confrontation with Emperor Zul.