Ultraman Nexus is a giant of light, born when a mysterious cosmic light merged with a "Deunamist" (a chosen human). He is the same entity as Ultraman The Next, who defeated Beast The One, but his form evolved as his body better adapted to Earth.

Characterized by his radiant silver body and glowing red Energy Core, his basic form is known as Anphans. In this form, he wields diverse abilities, including his signature "Cross Ray Schtrom"—fired by crossing the Armed Nexus bracers on his forearms—and the "Particle Feather," which launches blade-like energy waves to slice through foes.

Nexus first manifested on Earth during the emergence of the Space Beast Pedoleon, throwing himself into relentless battles against subsequent Space Beasts. By taking on the unique qualities of each Deunamist he bonded with, he could transform into various "Junis" forms. While four distinct Deunamists transformed into Ultraman Nexus throughout the series, all of them shared the ability to manifest his fundamental Anphans form.