When obtaining a Remembrance after defeating a major boss, you have two options: 1. Consume it to receive a large amount of Runes (20,000+). 2. Take the power of its namesake via Finger Reader. After consuming it, it will be lost. You have the option of taking it to Finger Reader Enia at Roundtable Hold (door to the right) to exchange for powerful items. Once exchanged it is lost forever.