The front cover of the non existing Manga with that name.
 
“Year X99X, Equestria fall in disaster, Disharmony rule the land, and everything is destruction between ponies and other creatures.  
The elements of harmony have been lost and it look like there is no hope.  
But a strange creature never seen before on equestria appears, Kenshiro, successor of the Hokuto Shin Ken.
 
Even when he dont know, his destiny is bring back harmony all over equestria with his assassin technique.”
 
this adventure feature a ton of already known Pony friends, even some sadly are not as friendly like they used to be.
 
Maybe some day we will be able to see this adventure Realiced.