>Personally I believe that whoever is doing the copyright abuse either is the original developer of the game or has some sort of relationship with them. Even though the "international copyright registration" site has no real authority, the documents they submitted include high-res 3D renders of models from the game, design documents, and source code commented in Japanese, none of which were publicly available prior to the copyright "submission".
Eh I am a bit of a collector and this line of thinking would let me establish copyright for a ton of games I have some precious treasures from.
Also I know a guy who worked for Sega and Nintendo for a while who is still sitting on a stack of design docs from his time in both, and he definitely doesn't own the IP for any of their games.
I suspect this person has located or inherited these items and is trying to establish copyright in the same way that Craig Wright is trying to pass himself off as Satoshi.
It's definitely all circumstantial evidence, but from all the recent stuff about Cookie's Bustle we know that whoever it is:
a) Is willing to at least tell the UK government that he's Keisuke Harigai (see this UK trademark registration: https://trademarks.ipo.gov.uk/ipo-tmcase/page/Results/1/UK00... )
b) Is comfortable with registering companies in shady tax havens and knows his way around international IP registration/enforcement
c) Has a bunch of private data related to Cookie's Bustle's development
d) Is unwilling to make any sort of public statement beyond sending takedown notices
Meanwhile, Keisuke Harigai:
a) Is Keisuke Harigai
b) Runs a company out of the Cayman Islands
c) Would have access to all data related to Cookie's Bustle's development because he ran Rodik
d) Has not made any sort of statement related to Cookie's Bustle since 2001 ( https://web.archive.org/web/20010725131942/http://www.idevga... ) despite people attempting to contact him after the takedowns started
Obviously nothing concrete but I think he's the likeliest candidate.