All three drops are fairly rare, so some strategy will help.

To speed things up, youll want to raise your Discovery to increase enemy drop rates.

you could further raise discovery by increasing yourArcane attribute.

Dominula, Windmill Village and the location of the Celebrant’s Skull in Elden Ring

Marikas Soresealwill provide some extra points of Arcane.

Turn east, and follow the ledge until you see a body with an item on it.

On that corpse, you will find the Celebrants Skull.

The location of the Celebrant’s Skull weapon on the map in Dominula, Village, on the northern edge of Elden Ring’s Altus Plateau