Climb the steps, then head west past the huge hole in the floor
Only Invisible is needed to get to the camp. You need to Invis for the Wespe just after zoning in. From entrance follow the stairs down and take the first left, You’ll come to a door which you need to open, So make sure the Wespe isn’t looking, cancel Invis, start re-casting and THEN open the door mid-cast. Otherwise the door will close by the time you fully cast Tonko. Also, there is sometimes a Torama behind the door, so be prepared with utsusemi and reraise. Go through the room with several Tonberries inside it, and eventually you will come to an area with stairs, Just after passing a Torama and hopefully the Tonberry Harrier. This is your camp, Zone is on the top of the stairs. If you are coming here at Level40 I highly suggest you cap a bare minimal in Enfeebling and Elemental magic skill prior to coming, Besieged is Ideal for this, Because of the level of the monsters inside besieged you will get a skill up very regularly here, And range from 0.1
0.5s nearly every spell, Spam dia for Enfeebling magic skill ups and any low costing MP Nuke for elemental skill ups.
Pros: -The pet is an elemental, which means you can Aspir them efficiently. -The Tonberry only calls Fire, Water and Light Elementals, Light elementals are very susceptible to Sleep, Drain, and Aspir so make good use of them -It beats Castle Zvahl camp. Cons: -Elementals are your prey; when attacked, they will walk a few feet and then start casting. It increases the time the master can detect the pet, increasing the chances of aggroing the master. Be extra careful when pulling -The hallway is narrow. Sometimes, it makes it harder to see around the corners and leaves the Tonberry less room to move around. You may see yourself waiting for longer periods of time because of this. -There is a Torama that occupies the same roaming area as the Tonberry Harrier, which aggros on sight. This can turn a good pull into a waiting game every now and then. -Light Tonberry Elementals can cast Diaga and Banishga which makes it tough for a BLM/NIN to solo, Banishga II can do up to 200 damage through shadows and you don’t have Silence to protect you from it. -A Torama can sometimes wander near the door on the way to this camp, and will aggro though the door.
40-44 – Castle Zvahl Baileys
600 NOTE: Be aware that this is a very, very dangerous camp, and it is possible that it’s not even worth your time even coming here as the chance that you are actually able to safely pull 
is very slim. Since you’re level 40, you can freely use the outpost warp in Xarcabard. Be sure to bring both Silent Oils and Tonko: Ichi tools. Blizzard II at level 42 will help out a lot. Camp Location(s): I found only one camp. It’s right at the zone into Castle Zvahl Keep. If you don’t know how to get there, here’s a walkthrough:
Enter the castle and head to (G-8). Before the intersection that leads to the torches that spawn Dark Spark, you’ll notice two narrow passageways on your left and right. Take the left passage and follow the path. Eventually you’ll come upon some orcs. You should arrive at the yagudo territory of the castle next. When you see their big hole, take a left, and head south past the hole. Go down the steps, and then double back to the north on the floor below. Follow the pathway and you’ll meet an intersection that goes only west and north. Take the north path, remembering to re-up sneak if any ahriman are nearby. Next, take a right, and you’ll see some steps that lead up to one ahriman and a bunch of demons.