Clue 1: Follow the purple marker to Ginkgo Village and talk to Damyoung.
Clue 2: Talk to Jangpo
Clue 3: Find Painter Manho near the Millenial Tree. Follow the purple marker.
Clue 4: Go in the waterfall.
Clue 5: Check what's written on the tombstone. Kill 30 Bloodshade Nefariox.
Clue 6: Kill the chief in a duel. Easy!