The Gray Gardeners is an order of masked executioners in gray robes who maintain and use the final blades to bring overthrown rulers in Galt to their death. They keep to themselves to avoid the same fate, resting in their anonymity to preserve their very lives. However, their position as keepers of the final blades grants them power as well.
Every final blade has its own unique name and people even bestow personalities to them. Whispers in the shadows of the Eternal Revolution speak that each final blades has unique powers that are granted to those who keep them.
The Monastery of the order can be found in Litran, but it is not easy to enter the town as an outsider. However, if one seeks a close encounter with a final blade, the Gray Gardeners are always happy to oblige.
Sources: Pathfinder Campaign Setting