Ultra Zero Fight is the new Ultra mini-series that debuted on Youtube on 2012, August 1st. Ultraman Zero's new ability to mode change into two forms first appeared in this series. One week after the broadcast on Youtube, Bandai Channel Episodes Free delivery limited the episode time.
The title and contents are a tribute to an older ultra mini-series "Ultra Fight", but here there is a consistent story. Broadcasting of Part 1 "The New Power" (8 episodes in total) were between August and September 2012 (the first episode aired in between Ultraman Retsuden episodes 57-64). The broadcast of Part 2 "Brilliance of Zero" began during December 2012.
Related Post : Source : ultra-wikia