Katsumi and Isami Minato, are brothers who live with their younger sister and father who runs a specialty store. One day, they found the R/B Gyro and R/B Crystals, which transforms Katsumi into Ultraman Rosso and Isami into Ultraman Blu. In which the brothers face their emotions with allies and against enemies, realizing important things they tend to take for granted. Although both siblings collide against each other, they willingly cooperate when fighting against opponents.
Minato Family
- Ushio Minato : A kind father of the Minato family and owner of specialty store Quattro M. As he lacks awareness of his sons being Ultramen, Ushio mistook his sons' behavior as teenage rebellion. His dream is to design clothes of his brand, UshioMinato and had provide financial support to his wife for her research.
- Mio Minato : Is the mother of Minato family who went missing for eight years prior to the series. As a researcher, her projects in the past were funded by her husband's clothing business.
- Asahi Minato : Is the youngest of the Minato siblings, a happy-go-lucky high school girl that is close to her brothers. She has a dislike of conflicts, which extends to the point of refusing to play rock–paper–scissors. On behalf of their mother, she performs the housework.
- Katsumi Minato / Ultraman Rosso : Is the eldest son who puts family importance above all else. After his mother disappeared, Katsumi gave up his dream as a baseball player to support his family. Despite his critical thinking ability, he is also hot blooded and incapable of observing his surroundings when playing baseball. He works as a clerk in his father's specialty shop and is able to pay attention to fashion trends.
- Isami Minato / Ultraman Blu : Is a university student studying space archaeology in honor of his long lost mother. He holds a huge respect to Katsumi for giving up his passion for sports to support their family. A free-spirited youth, Isami prefers to conduct interesting research instead of helping out at the store. Because of his clumsy attitude, he is incapable of expressing his gratitude to others.
Aizen Tech is a large company that focuses on space exploration and unknown energy research. The company is located on Ayaka City, the same area which the Minato family's Quattro M operates.
- Makoto Aizen : The president of Aizen Tech and general manager of research. He is friendly towards other researchers and has strong confidence from inside and outside of the company.
- D.R.L.N. : Is an artificial intelligence that assisted Makoto in his work.
The R/B Crystals which the Minato siblings used to transform into Rosso and Blu respectively contains the powers of past Ultra Warriors.
- Ultraman Taro : His power dominated the Taro Crystal, granting its user the fire-oriented form Flame. The crystal usually serve as Ultraman Rosso's main power of choice.
- Ultraman Ginga : His power dominated the Ginga Crystal, granting its user the water-oriented form Aqua. The crystal usually serve as Ultraman Blu's main power of choice.
