Ultraman Agul is the second Ultra Hero in the Ultraman Gaia series. Just as how Ultraman Gaia is the manifestation of the Earth, Ultraman Agul is the manifestation of the sea. Originally Agul had a few disagreements with Gaia on protecting the Earth which let to a few battles between the two Ultraman, however once the bonded human, Hiroya Fujimiya, regained his faith in humanity, the two were able to fight together against the Radial Destruction Bringer.