The title Ultraman is held by various members of the Residents of the Land of Light, though not all people from the Land of Light are named as such and few them seem to possess this title. The name was made by humanity as a name for the giant alien entities that had become their protectors, the Ultras seemed to have later adopted the name as that of their race the Ultras, or it may have been the name of their race in the first place and the title is purely coincidence. Some Ultras use their title name for their main name.
Earning the Name
The title Ultraman is given only to those who visit Earth, or at the very least protected mankind. In Ultraman Hikari Gaiden it was said by Ultraman King, that the name was given to him by humans and thus it was not his real name. In fact many Ultras do not use their real names, but they are referred to by their titles even among their fellow Ultras, though this may simply be the convenience of the viewer.
Ultraman 2011 Manga
In the 2011 Manga, the word Ultraman has greater meaning than before, it not only refers to the Original Ultraman and his kind, it also refers to the members of the SSSP who have taken up the mantle of mankind's protectors against alien criminals who have migrated to Earth. This title has become a sort of position, with the person in the role sporting an Ultraman Suit to assist them in their duties. So far three people have taken up the mantle: Shin Hayata, Shinjiro Hayata and Dan Moroboshi.
Related Post : Source : Wikipedia / ultra.wikia