Ultraman (ウルトラマン Urutoraman) is a Japanese Tokusatsu hero and the same name of his television series that first aired in 1966.
Ultraman is a follow-up to the television series Ultra Q, though it's not technically a sequel or spin-off. The show was produced by Tokyo Broadcasting System and Tsuburaya Productions, and was broadcast on Tokyo Broadcasting System (TBS) from July 17, 1966 to April 9, 1967, with a total of 39 episodes (40, counting the pre-premiere special that aired on July 10, 1966).
Bandai published the video game PD Ultraman Battle Collection 64 for the Nintendo 64 in 1997.
In the Book
Parzival, Shoto, and Daito go on a multiplayer quest together that goes through the movies of Ultraman. Upon completing the quest, they received an artifact called the Beta Capsule. The Beta Capsule allowed the user to transform into Ultraman once a day, for up to 3 minutes. Ultraman was seen during Shoto's escape from Frobozz where Daito transforms himself into Ultraman to cover Shoto's run for the escape ship (Kurosawa). He appears again in the Battle of Castle Anorak where this time he is used by Parzival to defeat Sorrento's Mechagodzilla.
Not in the Movie
In a Q&A interview for the upcoming Ready Player One film, Ernest Cline, who wrote the original novel and the screenplay for the film confirmed that Ultraman will not be appearing in the film. Cline revealed that they replaced Ultraman with the Iron Giant because they cannot get the rights to use Ultraman in the film. It is because of a legal battle between Tsuburaya Productions and "another company from Japan" named UM Corporation. Both companies want Ultraman to be in the film, "but the rights could not be cleared because of their legal battle over it", causing them to find a replacement for the Giant of Light.
On July 2018, Tsuburaya won the case and the Ultraman rights came back to them. However, the film's director, Steven Spielberg suggested to use Iron Giant as a replacement for Ultraman for the film, which he is okay with as he is also a fan of the Iron Giant. Although not really considered as a substitute, Daito transforms himself into a Gundam RX-78-2 also acting as movie substitute to Ultraman.