Someone has to know something.

Unfortunatly I have the same problem. Perhaps it is something extra cool like the supposed super unlockable(s)?

yes Maybe a super,the key looks extra nice.

ok where did you find this dead body with the key i had found a key in earth ream and im guessing these are superunlockables ill post mine when i found the location plz post where you found yours cordanites plz

yeah I believe it's around a-3 in the first part of the netherrealm in the right hand corner from where you start
you'll see 3 oni standing over a corpse and laughing