The next place you will be going in The Abyss is a tad safer then the place we where just at. A little bit to the south of the Undead you will find Drakes. The Drakes are level 38 and are also in a semi safe area. You can hunt the Drakes right above the Miren Fortress. Below is a map of their location:
Stay with these drakes all the way until level 38. Once you reach level 38 you will want to head west to Miren Island.
Over on Miren Island you will find level 40 Balaur. The Balaur here will take you all the way up to level 40. In addition to the Balaur on Miren Island you can also head south to Kysis Island where you will find level 40 drakes to kill. Go to where ever you're not getting ganked a lot is my motto.
In addition to the Drakes being on this Isle you can also find other mobs to kill to the south. Also right above where it says "Isle" on the map is a little pack of Asmodian NPC's with two quests. The quests kinda suck but more importantly it is a good place to place a Kisk.
Once you reach level 40 you have a decision to make. Hang out here at the Balaur or Drakes for one more level or leave The Abyss and merge with my 40 - 50 Guide. Sadly there are no mobs over level 40 for you to grind here.