How do you get the dark dragon blade in ninja gaiden black

there are two ways actually:

1. On a successful play (complete the game once then, when the last cutscene ends, the save game screen comes up and then save over the slot you are playing on) , once you retern to the hayabusa village the second time (through the teleporter), go up into the building you are supposed to be going, and it will be sticking in the floor in the top left corner of the room.

2. collect all 50 golden scarabs and return them to muramasa the shop keep. (this will only work on hard mode, I'm not sure if it will work on very hard or master ninja mode)