Easy way to unlock all characters
Finish the game on easy but do not overwrite your save By finishing on easy you would have unlocked two of the characters After that go to the game settings option and switch the game difficulty to hard and then go to story mode but select Continue instead of New Game It will simply play the ending and after the ending credits you will unlock the last two characters without having to replay the entire Story Mode on hard
Unlockable Characters
How to unlock characters for all modes other than story
UnlockableHow to unlockDanBeat Story Mode on hard difficultyLilithBeat Story Mode on any difficultyMoritzBeat Story Mode on any difficultyShoukiBeat Story Mode on hard difficulty