Final Fantasy XII The Zodiac Age HD - NC - 100% - Medallion of Love and Lusterless Medallion

You will need to travel to Archades and speak to Roh'kenmou in Charlotte's Magick Shop. He will say he sold the medallion to man named Otto, which if you remember, you will find him in Old Archades in the Alley of Muted Sighs. The Proper Gent/Otto will be sitting next to a woman. He will then give you the Moonsilver Medallion. Head back to the Magick shop and speak with Roh'kenmou.
The Third Medallion will be back in the Nabreaus Deadlands, you will need to go to the Muted Scarp, and speak with Roh'kenmou again. They will have you travel to the hidden area, the same place that you fought the Roblon. Once there you will get the final medallion.