an Entity references as follows:
Return of Ultraman (帰ってきたウルトラマン, Kaettekita Urutoraman) is a Japanese tokusatsu science fiction television series produced by Tsuburaya Productions. The fourth entry in the Ultra series, the series aired on Tokyo Broadcasting System from April 2, 1971, to March 31, 1972. It became successful enough to inspire a second "Kaiju Boom" in Japan, with rival studios producing their own tokusatsu shows and Tsuburaya Productions producing additional Ultraman shows annually for the next three years. Prior to the series' release, Ultra Q, Ultraman, and Ultraseven were stand-alone titles however, Return of Ultraman is the first installment to unite the first three shows into an interconnected universe.