A monster that lived in Sagami Bay in ancient times, it is said that it is a type of bird that migrated south due to the changing seasons.
It can fly at Mach 2 speed and specializes in surprise aerial attacks. It is also highly intelligent.

After being saved around Kaburaya Islands, it started living at the Monster Reservation Center.
There, it became good friends with Musashi Haruno, who often visited.
However, as it was resting in its nest, it became infected by the Chaos-Header virus and became violent.
It broke the shield that was protecting the Kaburaya Islands and headed towards the J1 area.

Now transformed into Chaos-Lidorias, it began destroying the city.
Ultraman Cosmos in his Luna Mode managed to return Lidorias to its normal form using Luna Extract before sending it back to the Monster Resevation Center.
Ever since then, when Musashi would get in trouble, Lidorias would hurry from the Kaburaya Islands to help him out, assisting with his battles against monsters such as Golmede or Chaos-Header Mebut.