Located between the lower claw and tail in the middle of the ocean; home of the Nagas. (Someone who speaks Naga should probably write down what all the signs say here.)
Guide To Ancient Vesimas Farming (Incomplete)
Be wary ye of little faith, this place is best challenged by those with 20 levels of experience or higher. Bring some potions for water breathing (if you don't have it naturally), cold/shock endurance, resistance/immunity to fear, paralysis, confusion, and poison.
Starting from the entrance into Vesimas, travel up and to your right. Stop by the bed and breakfast if you'd like to create a save point, on your right is a building on some dirt titled, "Gateway to Ancient Vesimas;" go ahead and enter it. The whirlpool in the upper left is the entrance. Go ahead and throw on cold resistance, water breathing, and whatever else you need. From this point on you'll be underwater.
You will probably stumble across liquishock and white dragons when first entering, floating eyes too. You will eventually encounter water shoggoths and possibly a Cacodemon as well. Most of the enemies are manageable, save for the CacoDemon; if need be you can just run past it. There's a switch in the top right corner in the map, flip it and head down to the bottom corner. There's a gate that should be down now, go in and flip the one of the two switches that doesn't bring the gate back up. Go back out, a little to the left, and then immediately back down the the bottom wall and to the left, there should be two switches side-by-side; flip both of the switches. Before I forget, if there's a poor innocent fish in front of your precious switch that you need to flip, type 'kill fish' in the command box to murder that poor sucker. You're a monster, by the way.
Closer to the switch you flipped initially, there's another gate that leads down a short narrow path to two more switches, do the same as before. You're going to start noticing a pattern here. Now go up to the very top of this section, locate the gate that leads to the next section, it should still be closed. If not, why are you still reading this part? Anyways, go straight down from here, oh hey look another open gate! Flip the switch then go back up, the gate is now open, yay!
More dragons in this room, also some slimes. Clear out the area, there should be two free roam levers to pull. Go find 'em, then on the right sight of the map there's a gate that will open, go inside and flip the switch in the bushes. Oh, before I forget, prepare to find switches in bushes when farming this area.
Move toward the middle, and find the other open gate. Only flip the switch IN THE BUSH (there should be three). Go further left, there should be another wide open gate, flip the switch. Then, if you go up, the gate leading north should be open. If you go up, there's a lone tower. This is where you're supposed to be right? WRONG. Go back down into the previous area, and to the southeast. There's another open gate, go down.
More baddies, clear 'em out. This place is a bit different, it's more linear. Find all the free range switches and flip them, a few open gates to different parts of the room, so a few are redundant. Look in corners, nooks, and crannies, none of the free range switches are that hard to find, but at least one is in a bush, so keep a keen eye! Eventually you should reach the bottom right corner of the room, where a closed gate lies. At this point, if you've caught all the switches, time to do a little backtracking.
Now we're going to go flip the switches behind the gates that were closed. The first one is down from the large gate, go left until you're in the middle of the room, go up and there should be an open gate right above one of the free range switches you flipped earlier. Inside is two switches side-by-side, and a mushroom! (Maybe?) Do your thing, and on to the next one! Starting from the entrance of this area, to right a little, and down. There's a very small room behind the gate, by another open area switch. Flip the thing! Go back to the start, go straight down, see the gate that sorta acts like a shortcut? Waddle up next to it, and if you're at the right angle, you should see another gate in this tight corridor. Wiggle your way through to the end, and flip the switch. Be sure to murder any poor fishes that are in your way you disgusting filth. Go all the way back to the gate to the new area, and it should be open for you to carry on! What's that? It's not open!? Sorry, can't help you, there's no hope left for you.
Congratulations, you've entered AV! From this point, as far as I can tell, it's free range chickens. Someone more knowledgeable than me should take up the mantle here because as far as I've been able to tell, there's just a ton of baddies to kill, and this is where the meat of your farm is. Naga zombies have a good chance to drop some decent loot. You'll eventually stumble across barrel puzzles, one of the floor switches is under a bush that's very hard to spot, the bush will be down a tight corridor and it's only in one area so don't let this sentence make you paranoid. Be sure to contribute if you find anything new, I suffered through this so you don't have to! Oh, and be sure to shout, "Thanks Mr. Savy!" in the chat if you followed this guide! I'm desperate for appriciation.