What is the fine-grained topic of the following text: Katsumi Minato/Ultraman Rosso played by Yuya Hirata, Isami Minato/Ultraman Blu played by Ryosuke Koike, from the highly popular TV series “ULTRAMAN R/B (Ruebe)” on air at 9am every Saturday on TV Tokyo, will be joining every Ultraman Battle Stage. Only return the topic.
Katsumi Minato/Ultraman Rosso and Isami Minato/Ultraman Blu joining Ultraman Battle Stage from the TV series "ULTRAMAN R/B (Ruebe)".