The Bond of Siblings (兄弟の絆 Kyōdai no Kizuna) is the second episode of Ultraman R/B.
Despite his younger brother taking the ability to become Ultraman in stride, Katsumi is afraid of the power he’s obtained. Their younger sister, Asahi, whose catchphrase is “Happy♪”, uses her healing nature to help the two brothers, who have clashed over their views. Suddenly, a monster appears and Isami is unable to move when he’s pinned down.
One night, the two Minato brothers went out to train in the forest. The two transformed into their respective Ultras (Ultraman Blu and Ultraman Rosso) and practiced fighting skills, then later learned to fly. Isami, as Blu, decided to test out his Aqua Strium on a nearby hill, but was scolded by his brother for being careless.
The next day, Ushio and Asahi are disagreeing over fashion choices, when suddenly, Makoto Aizen appeared on screen and talked about the recent destruction of his building. Afterwards, the two brothers are seen sitting in a park, discussing about their role as Ultras. The two break into a fight and Isami runs off. Asahi joins Isami and tries to cheer him up, but to no avail. A Black King, summoned by the mysterious summoner appears and begins its attack. Isami runs towards a building, preparing to transform, until he hears his sister's voice calling out for him. Isami calls for her to run away but Black King spews his flame breath and traps Isami under the rumble. Katsumi arrives at his siblings' location and saves Asahi from another blast of fire from Black King, as she falls unconscious. The two brothers regroup and hands Asahi to their father. Then the two transform into their secondary Ultra form and begin to battle Black King.
The two Ultras tried hard to hold off the beast, but were easily beat down by it. Then they tried their combo attack from the previous episode, however, it was also foiled by Black King with its flame breath. Just as things were looking bad for the Ultras, they switched into their default form and ended the battle with their amazing coordination. After the battle, the mysterious summoner appears once again to retrive Black King's crystal.
Back at the Minato clothing store, the two brothers once again see Aizen on the television and questions his odd behavior and knowledge on the Ultras. Once again Ushio and Asahi are having a conflict over a matter, this time its the book Ushio kept from his wife. As the book is thrown onto the ground, Isami recognises the strange drawings on the bottom of the page to be the R/B Crystals that the brothers use to transform. He shows the drawings to his brother and both being to wonder about their mother's knowledge on the crystals.
- Katsumi & Isami: R/B Crystal Navi!
- Isami: We are going to be studying R/B Crystals now Katsumi!
- Katsumi: Yeah. Today's crystal...is this!
- R/B Gyro: Ultraman Ginga!
- Isami: The Ultraman who comes from the future, Ultraman Ginga, uses many various techniques in battle. Using the Ginga Crystal, we can transform into the form of Aqua!
- Katsumi & Isami: Be sure to watch next time!
- Katsumi Minato (湊カツミ Minato Katsumi): Yuya Hirata (平田 雄也 Hirata Yuya)
- Isami Minato (湊イサミ Minato Isami): Ryosuke Koike (小池 亮介 Koike Ryōsuke)
- Asahi Minato (湊アサヒ Minato Asahi): Arisa Sonohara (其原 有沙 Sonohara Arisa)
- Ushio Minato (湊ウシオ Minato Ushio): Ginnojo Yamazaki (山崎 銀之丞 Yamazaki Ginnojō)
- Makoto Aizen (愛染マコト Aizen Makoto): Motoki Fukami (深水 元基 Fukami Motoki)
- Ultraman Rosso: Hideyoshi Iwata
- Ultraman Blu: Akira Okabe