Marsh Zombies, the same ones you kill for the Blood Saber quest and the fertilizer quest. They're magic-resistant, and also swarmed by profarmer bots (yeah, I know it's amazing they can make a profit, but they do the quest and keep deleveled enough to have full newbie helper buffs), so bring some sps and patience. GL :)
They are NE of the swamp right around where the map changes color for the swamp back to the "grass", at least they were in C3. It's best to use a target macro to find them.