The Cultist’s Blood is a Legendary Crafting Material found in Act I. While there are a few sources it drops from, you want to farm the one that spawns permanently, not a random target, right?
Go to Halls of Agony Level 1 and kill Cultist Grand Inquisitor. He spawns every time you launch a game.
The Cultist’s Blood is used to craft a Legendary Dagger: Blood-Magic Edge. The Punyal required to craft this weapon can be farmed at the same location from the Torture Tools (weapon racks).
Blood-Magic Edge
Materials
| Item | Item name | Amount |
 | Punyal | 1 |
 | Arcane Dust | 50 |
 | Veiled Crystal | 20 |
 | Forgotten Soul | 1 |
 | Death's Breath | 1 |
| Cultist's Blood | 1 |
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