Each of these series will cross over in an ongoing collaboration between the series’ producers, Toei, Tsuburaya, Toho and Khara. The project is called the Shin Japan Heroes Universe (SJHU) and while nothing is known about exactly what kind of collaboration it will be, it aims to represent Japan’s heroes. Hideaki Anno is a director for all four movies in the collaboration. However, Shin Ultraman and Shin Kamen Rider have not yet been released.
The movies in the SJHU are all reimaginings of classic Japanese series with darker undertones and updated effects. For Toho, Shin Godzilla acted as a reboot of their Godzilla franchise and updated several of the metaphors that Godzilla originally stood for, as Godzilla was a metaphor for nuclear devastation and the Godzilla from Shin Godzilla is a metaphor for ecological disaster and nuclear power in general.
Evangelion: 3.0+1.0 Thrice Upon a Time served as the conclusion of the Rebuild of Evangelion tetralogy. The film series acts as an alternate timeline to the main Neon Genesis Evangelion series, introducing new characters, Evangelions, plot points and antagonists. While the first three movies generally followed the original plot, Thrice Upon a Time ended very differently than the series. The Japanese title for the movie is Shin Evangelion: Movie Edition :||, relating it to the other “Shin” movies in the collaboration.
Thrice Upon a Time is the only movie in the collaboration that is animated. There has been no information on whether the SJHU will be animated or live action, but information regarding the project is coming, according to each of the companies.
Not much is known about how Shin Ultraman and Shin Kamen Rider will change the plots of their respective series.
The emblem for the Shin Japan Heroes Collaboration was designed by Mahiro Maeda, an animator and director that has worked on Shin Godzilla, Shin Ultraman and the Evangelion Movie. The emblem features the faces of each of the main heroes from the movie in a flower design with four petals.
The SJHU website refers to 2022 as the beginning of the “Shin” era and asks fans to stay tuned for updates.
Source: Super Japan Heroes Universe