Originally posted by silver384
the trophy of difficulty legend does not release
It does, it's probably just that you had never created a Legend difficulty save on your copy of the game before. The Legend difficulty trophy only seems to pop after the game knows you're playing Legend difficulty, which for some reason doesn't happen just from loading someone else's save. A few options, although I haven't tested the third:
If you beat it on Legend difficulty using this save, do it again. That seems to trigger it, although that might only be if you let the profile save itself after the credits the first time you beat it on Legend difficulty. Make sure you keep your profile save from the first time you beat it on Legend because that's probably where it stores the information about difficulties played. Meaning, you can overwrite it when saving, but don't delete it and don't take someone else's profile save.
You can also start a new game on Legend difficulty, skip past the cutscenes, and save as soon as you control Kiryu. That ensures your game knows you're playing Legend difficulty. Then load up this save again and beat it again. Again, keep your profile save.
Last - this should work but I'm not positive simply because I haven't done it and haven't seen anyone else say they've done it - Load this save, save immediately, then beat it. It should do the same thing as above, registering that you've started a game on Legend difficulty. Again, between the time you make that save and the time you beat it, if you happen to exit the game for any reason, keep your profile save.