A French blacksmith who did this knife using a meteorite and mammoth ivory.
Edit: a bit more details on the blade: he melted the meteorite himself, however since the meteorite did not have any carbon and had a really high nickel content or would have make a terrible steel so he added a bit of carbon and some raw iron do dilute the nickel.
Except for that the blade is entirely made from the meteorite.
Plus 3 all outsider bane , shiftsilver, longsword.
While the sword is drawn it, acts as a continual zone of truth. ( the user is not immune.)
The user is also continually protected from good and evil.
Anyone being stabbed with the Sword who is possessed by some kind of illusion, or delusion has it removed, including if it was voluntarily placed on them.
If the sword is used to attack, someone who is some kind of living lie, they must roll wisdom save or be destroyed. Even so they take triple damage.
( both of the false and true hydras would need to watch out)