Vyre noble legs (unscented) are a piece of a vyre noble disguise which has not been scented with the blood of a vyre noble. It is obtained by giving Polmafi Ferdygris a vyrewatch outfit during Sins of the Father. After obtaining it from Polmafi, it can be found in a chest within the Myreque Hideout.
It must be brought during the fight with Damien Leucurte in order for it to become vyre noble legs.
When inspected, the chatbox states "The legs of a vyre noble disguise. They need to be scented with vampyre blood before it can be used."