CP Cerro x Boyce. Boyce (Voice) debuted in the 2012 collective stage play, and is Zero's cub (cv: Tomohiro Yamaguchi, the original vocalist of Voyager).
The timeline is before Ultraman Galaxy, and UFZ also appeared together.
Originally included in the 2014 doujinshi "Power of Voice" of the same name, it has been sold out.
Conception: