How do I restore my master key if I don’t have access to the email?

Do you remember the email used? I had a similar problem a few years ago as I moved from an iPhone to an android, if you know the email then go to that email say on Gmail or the Icloud and reset the password for the email then you can have access to your password (note once you've reset your password on the email restart wildcraft as it can crash). You should be able to get your master key however, I had to spend about 30 mins to get it. If you still can't then in either the Google play store or the app store you can find RocketGames email address and you can send them an email 😃