(Coming-of-age story + no System + parallel Ultraman world + one female lead)
There are countless Ultramen across countless parallel universes.
But in one universe, all the Ultramen have been cut off from it. Their light, however, gathers in this universe and gives rise to a new Ultraman: Diga.
He is the fusion of all universes, and their destroyer as well.
The parallel universes begin to expand and writhe. They all start merging into this universe, and the universe he lives in is on the verge of destruction.
To save his universe, Ultraman Diga begins traveling through different universes, writing a story of his own.
