Im not sure if this has ben brought up before but i thought that since letters play a large part of MK:DA what if this final secret thing is to do with letters? I wrote down all of the gold koffins letters.

AI AR
FD FM FW
KI KR
PD PM PW
UI UR
ZD ZM ZW

See the pattern? now what I did was take down all the unique letters in that list. Taking out all the duplicates. the list was shortened to
A I R F D M W K P U Z to be honest, im not really good at anagrams. but i know that there isnt enough vowels there to make a short scentence or even a long word. so what I did now was add in the first letters of each koin type.

S = SAPPHIRE
O = ONYX
E = EMERALD
R = RUBY
G = GOLD
P = PLATINUM

now theres some more letters that MIGHT be able to be added, the colour of the koins

B = BLUE
G/S = GREY/SILVER
G = GREEN
R = RED
Y/G = YELLOW/GOLD
S/W = SILVER/WHITE

I hope you see what im trying to do. Its complicated enough to write down whats going through my head

anyway, i was thinking that maybe the letters here could be rearranged into some word or something that may be able to be put into the Profile name tab. I believe that there is a word that you might have to input as a name in profile to unlock this "final secret". am i just chasing a dream, are there too many possibilities??? maybe there are, but 2 heads are better than one, so i thought id share my idea with you's and see if anyone might try thier hand at this wild theory of mine...