The hardest part of this quest is navigating through the ruins of the Domain of Secrets while avoiding the many large groups of level 24 Margonites that populate the area. These groups are not difficult to take down even with a full party of henchmen, provided that you can take it one group at a time. Getting trapped between multiple groups of Margonites is a sure way to rack up DP. Thus, the best strategy would be to carefully progress through the route while keeping a close eye on nearby mobs. Don't take a chance until you're sure they won't get too close while you take out the single group blocking your path.