I have learned this in cabal PH, when I came back to visit my homeland Philippines, I used my relatives account to play his WI and he had no merga ring. With nothing to do I decided to run eod but then this shout of another player caught my attention coz he was cursing bout how eod wont drop the effing ring after so many runs and it was hillarious in filipino language... then two to three people replied back at him, they said that the best way to get the ring is to do all the quests of the dungeon. but before doing so, you got to abandon quest and retake it again (as if refreshing the process of taking the quest) if you have tried so many times.

Well I dont know if you guys tried doing it but it worked on me. to both the wiz in PH and my FA and fb here in cabal NA. my FA had a total of 10 runs, and my recently created fb (115 now) just had 1 run to get it.