Greirat is locked in a cell in High Wall of Lothric that requires the Cell Key . You can find the key in the building that overlooks the Winged Knight’s courtyard and return to the cell to release Greirat. who’ll give you the Blue Tearstone Ring and ask you to find a woman names Loretta in the Undead Settlement. At this point he’ll move to Firelink Shrine and become a merchant, located to the left of Andre the Blacksmith.
After finding Lorettas Bone:
Speak to in Firelink Shrine to officially obtain the ring and then refresh the area and speak with him again for the "Curl Up" gesture. You can now refresh the area and he’ll offer to pillage the Undead Settlement, which will expand his inventory - he’ll return after defeating any boss.
After reaching Irithyll of the Boreal Valley:
He’ll offer to pillage again, but make sure you’ve been working on the the quest lines for Unbreakable Patches and/or Siegward of Catarina before doing this.
- If you've recruited Patches, and not Siegward, you'll need to inform him that of Greirat's location, before you beat the next boss.
- If you've been following Siegward's quest you'll need to exhaust his dialogue in Irithyll of the Boreal Valley, before you beat the next boss.
After reaching Lothric Castle:
He’ll offer to pillage again, but he’ll die no matter what you do to save him.
- To keep him alive, refuse to send him and he'll remain in Firelink Shrine.
- To gain additional items from the Shrine Handmaiden, send him and then retrieve his ashes at the Grand Archives.
- 1,000 Souls
- Greirat's Ashes