Unlock Location:
- Progress through the story until reaching "Unpaid Tab" a Main Quest in Queen's Cradle area.
- You will encounter Driller Hole, Minor campaign boss.
Farm Method:
- Defeat Driller Hole and finish the main story mission.
- After completing the story mission, return to his arena.
- Use the Encore Machine nearby to reset the fight.
- Repeatedly defeat Driller until
Artillery Fuse drops.