Unlock Location:
- Progress through the Terminus Range region, heading south where it borders the Fadefields.
- Unlock the Old Scrape Drill Site, where Saddleback resides as the boss.
Farm Method:
- Defeat Saddleback, who can drop
War Paint in addition to 
Lucian's Flank. - Use the Encore Machine to reset the fight.
- Repeat farming runs for War Paint.