Memory was one of the two Logrusfoils that was required by Annadil to open the Gate of Revolution. It was originally given to House Alars, before Annadil stole it back for this purpose. Its special property is that it aids its wielder in shadow walking.
After Annadil's defeat, Shaft claimed it. For the most part, he kept it in his armory to be grabbed via trump when he needed it.
After Shaft died, it went missing along with the entire contents of his armory. It was believed that Lord Loewen of House Helgram was to blame for this theft, although he recently swore to the Bride of the Serpent that he had nothing to do with Shaft's death.