Wow, level 70 now! That's a far cry from the poor noobish Rogue 60 levels back. Therefore, it is appropriate that you show off your glory as a Chief Bandit by Assaulter-ing every monster in sight. But how to become one...? Read on!
Go to El Nath - Chief Residence and speak to Arec. After talking to Arec, head back to Victoria Island and talk to Dark Lord which is located in Kerning City. Next, find the Door of Dimension located at Monkey Swamp II and it'll bring you to "The Path of the Glittering Crystal". Walk until the end of the path and enter the portal to defeat Dark Lord's dark side to obtain the Black Charm.
Return to Dark Lord and exchange the Black Charm for a Necklace of Strength. Return to El Nath after that and give the item to Arec. Head on to the Holy Ground at the Snowfield (Sharp Cliff II). 1 Dark Crystal is required to answer 5 questions to obtain the Necklace of Wisdom. Again, head back to Arec in El Nath and give him the Necklace of Wisdom. And kaboom, you're a Chief Bandit! Feel free to jump for joy, Then Gratz ConGraTuaTion.