On December 08, 2020, Nintendo of America Inc.'s trademark filing, US Serial Number 79289925, Eternal Darkness, was registered with the United States Patent and Trademark Office (USPTO). The application was originally filed May 14, 2020, but claims priority from international registration 1541696A originally filed January 15, 2020.
Below is the registration certificate:
Source: https://tsdr.uspto.gov/documentviewer?caseId=sn79289925&docId=ORC20201122020932#docIndex=0&page=1
What does this mean then, in comparison to previous filings for the Eternal Darkness trademark? The major difference is that this is an actual registration and not a Request for Extension of Time to File a Statement of Use as we have seen many times in the past. Thus, a 36 month window in which NoA can file requests for such extensions is void in this context. They will have to file for a Declaration of Use however, as stated in the registration certificate:
First Filing Deadline: You must file a Declaration of Use (or Excusable Nonuse) between the 5th and 6th years after the registration date.
As usual, a trademark application is not evidence of a game being developed. In previous applications for certain extension requests, this has been under "ongoing effort" though (but is standard practice and nothing eyebrow-raising):
Source: https://tsdr.uspto.gov/documentviewer?caseId=sn87274495&docId=ESU20191106155005#docIndex=4&page=1
This could mean a number of things, from a simple meeting to prototyping (a new game, a port/remaster etc.). As for the active and registered application, I would assume its purpose is to avoid the process of having to abandon an application for which a Statement of Use has not been provided in a timely manner, for just to file a new trademark application again and again.
Other countries/regions where Eternal Darkness trademarks remain active include South Korea, Mexico, Canada, EU, Australia and Singapore.