The Blades of the Darkmoon are just one of the many covenants you can find in Dark Souls III, and are also a throwback to the faction of the same name in Dark Souls 1. To join them, and again become a disciple of Gwyndolin of the Dark Sun, there are a few hoops that you’re going to have to jump through.
Firstly, you’re going to have to find Sirris, of the Sunless Realms, who luckily appears in Firelink Shrine when you first talk to Horace and Anri of Astora on the Road of Sacrifices. Once you’ve had a chat, she’ll give you the Darkmoon Loyalty gesture, which is the key to this whole operation.
WARNING: Don’t join the Rosaria’s Fingers covenant or Sirris will leave, along with the gesture that you need!
After this, you’re going to have to make it all the way to Anor Londo. Once you’re there, turn around from the bonfire to the rotating stairway that you arrived on, go down to the bottom, and like the true Souls’ masochist you know that you are, walk out into the void. You’ll be surprised to notice that you’re still alive, much like the same stairway in Anor Londo in Dark Souls 1, and the path to Seath.
If you keep walking along, you’ll come to an area where you can drop down and you’ll notice a strange crowned beast in a chair that looks like a baby Crossbred Priscilla. This is Company Captain Yorshka, and to join the covenant, you’re simply going to have to talk to her. If you didn’t listen to my earlier advice about Sirris, you can also kill her to get the item you need to join the covenant, but this also means you can’t rank up, and those rewards are pretty cool to miss.
- 10 Proof of a Concord Kept will net you the Darkmoon Ring, which increases FP restored by your Ashen Estus Flask
- 30 Proof of a Concord Kept will get you the Darkmoon Blade miracle, which is basically another magic weapon spell, but really powerful.
Check out the Dark Souls III wiki for more help with the game!