A monster born when the minus energy emanating from human pain and sadness took on a physical form. Crescent is also the first monster that Ultraman 80 fought on Earth. Crescent burrows underground to collect minus energy, and maneuvers above ground in the form of a shadow that most people cannot see.

Crescent can move at high-speed underground. it traveled around Japan, destroying highways, causing fissures and earthquakes, toppling forests, and altering rock formations. Crescent finally showed itself above ground after storing enough minus energy. It was struck by a sudden lightning bolt upon emerging from the ground and changed from a shadow into a solid form. The monster appeared near Sakuragaoka Middle School where Takeshi Yamato worked. The Terrestrial Defense Force and UGM mobilized immediately to stop the monster, but their attacks had no effect.

Ultraman 80 arrived and Crescent started to fight the Ultra. Crescent initially overpowered the hero using heat rays and his superior strength, but 80 was suddenly empowered by the onlooking children cheering him on, and Ultraman 80 defeated Crescent with his Succium Beam.