Ririka Kato, nicknamed "Blaster Ririka," is the mother of Marika Kato and the former wife of Gonzaemon Kato. She was once a renowned space pirate who served alongside her husband as a crew member of the Bentenmaru. After her active piracy career, she became an air traffic controller.

Marika Kato usually calls her by her given name, Ririka, though she uses "Mother" in serious or formal situations. In her later years, Ririka bears a strong physical resemblance to her daughter. Her documented pirate past established a formidable reputation. Schnitzer, the Bentenmaru's tactical officer, was her friend during their piracy days.

Skilled with firearms, Ririka conducted gun range practices with her daughter using notably large weapons, reflecting her assertive and capable nature after retirement. Her background illustrates a shift from space piracy to a conventional profession while maintaining ties to her past through her daughter and former crewmates.