This is Dragon Slayer: The Legend of Heroes for the PC-8801, a floppy disk game set with manual and original box. All text is in Japanese.
The disks have only been partly tested, and as is common with floppy disks this old, mold may be present, so full playability through to the end of the game can't be guaranteed.
Note: this set includes additional disks originally sold for the Sorcerian game — you'll need the original Sorcerian disks to play this Pyramid scenario.
