This sword is splotched over with black and blue stains and feels extremely light. It has a scabbard covered in old parchments and weathered runes.
As an action you can transform the sword into an ink pen or back into a shortsword and when you do so specific runes across the scabbard glow softly. Once per day an action you can activate the sword by running your hand across the runes on the scabbard. Inky black tendrils curl out from the scabbard creating a copy of a set of runes on the surface of the blade. For the next 10 minutes when you hit a creature with this weapon that creature has disadvantage on the first attack roll it makes before the end of its next turn.
Additionally, once per short rest you can create 1d4 sheets of parchment as an action and yet another section of runes glow softly. Any previous sheets of parchment you have created in this manner are destroyed when you create new sheets unless they have sufficient information on them to be considered valuable artistically or intellectually.