Nasuti Yagyu, the character's original Japanese name, is approximately 17 years old when the series begins. She inherits extensive scholarly knowledge of mystical artifacts and history from her grandfather, an expert in these fields. This expertise makes her the group's primary researcher, consistently providing vital intelligence on enemies, mystical armors, and strategies against supernatural threats. Nasuti shoulders significant logistical responsibility by transporting the group in her van, as none of the warriors can drive. She forms a mentorship and protective bond with Jun Yamano, a young boy separated from his parents during the initial demon invasion. Nasuti displays perceptive tactical understanding in critical situations, exemplified when she orchestrates a plan where Jun feigns severe injury. This successfully triggers Shu Rei Fan's righteous fury, breaking his psychological block and restoring his ability to summon his armor after a loss of faith. Her role encompasses academic support through research, practical support via transportation, and emotional support for both the warriors and Jun.