+1, and on that note, good luck. Before I say this, let me just state I'm a noob when it comes to decrypting; I usually just use other people's scripts. I just spent the last couple of hours looking for any easy decryption method so that I might do a "close enough" translation for the UI and maybe some dialogue (probably using google trans with a good amount of guesswork), but the dev seems to have buried the decryption key in rpg_core.js, or something like that. Not only that, he also (from what I can tell, javascript isn't my forte) uses references to the decryption key rather than the string of key numbers itself. I tried using Petschko's decryption key script at the end of the file as he recommends, but it didn't do anything. If anyone else wants to take a crack at it, best of luck. Also, I believe this is made in RPGMaker MZ if that helps.
Edit: Nope, it's in MV