This is a Side Quest in the Orient (Act III). Bao Er in the center of the Village of Zhidan tells you of a terrible monster hounding the road to the next town. Search the Jingyang Woods right behind the village for Bloodfang - Tropical Arachnos Warlord, a pretty weak Arachnos Runeweaver boss monster, and kill it (the yellow dot on the map on the right marks its usual location). Quest finished.
If Bloodfang is not in its usual spot, you can either go to the main menu and try again or search for it. It sometimes lurks far southeast of the first bridge.
- Experience: 27k / 70k / 190k (normal / epic / legendary)