Grishas are rare in Mortal Shell 2, but you can find a respawning one inside the secret Desolate Keep dungeon inside Marrow Keep. If you go to Sester Genessa's arena, you can find a marked wall in a dark corner to the left of the stairs. Hitting this wall will reveal a cave with a chained chalice in the middle. Destroy the chains, and you'll reach the best Grisha Remnant farming spot in Mortal Shell 2.
