First of all, leveling at abyss_03 is pretty tedious. You can go to for_fild06 and kill Uber Porings, Poporings and Drops to level, it is a lot faster that way. As for your damage, it could just be their stats/build or their equipment. There is Knight/King/Friggs shields which give 17%, 20% and 25% demi-human reduction respectively, and Usakoring Card which reduces demi-human damage by 35%. There's also your own damage modifiers (Hydra, Goldenring, Skeleton Worker, Silver/Normal Turtle General, etc) that are taken into account not to mention their weapon (custom weapons are pretty strong compared to normal NPC weapons) which could be why your damage is so low.