If you want to delete your crystal realms account, send an email to crystalrealmsgame@gmail.com asking to delete your account.
This email should contain your username, and it should be send from the same email address that you used to register your account.
After this your account will be deleted within 7 buisiness days.
Note that you will not be able to recover any items or in-app purchases after your account has been deleted. Your data might still be stored in server backups for up to 1 month.