Exploiting the Execution Room and the Campfire Quest
The Execution Room, which is new to Zenonia 3, is a very easy way to level your character early in the game. Once you get to the town of Delfoy do the little side missions and a few of the main ones until you get level 10 or higher. This wont take long if you are adamant. Once you can at least clear one room you get about 2800 XP for this which is a massive amount for a low level character, you also get very nice (albeit random) equipment that is usually magic or above classed. The equipment that you get is a level or so above you which will give you something to work towards. You will die a lot, but don't use any origins of life unless you have lots of them or a lot of Zen on hand. There is no penalty for death in the Execution Room, you just get sent to the very first room and you have to clear it all over again. The monsters and mini boss legendaries that you fight will be randomized each time you enter a room, so don't expect a "watering" creature on the first floor every single time. You are gonna have to grind it for a while to fully exploit the room, but each room cleared stacks XP and that gets to be a pretty large amount for just a few rooms cleared which can get you a level or two in just a few minutes if you play your cards right and heal when necessary.
Note: You get a little bit of HP and SP back when you enter a new room, and when you die you get it all back.
Shamans and Mechanic Launchers will probably do the best here because they have the advantage of range. The guys who have to do all the fist to fist hitting will have to do some hit and run tactics because the monster increase by one level or so from room to room and they start off stronger than their counter parts that appear outside the room.
The Campfire Quest offers the Shaman class a chance to take on the Level 47 Devil Grandiers, after the cutscene where Chael and Celine talk and it tells you to go talk to Runa, DON'T walk past here and go south. It will take you to the area where there are wooden barricades between you and the Grandiers. Shamans can get close to the fence and fire magic bolts at the Grandiers and occasionally your bolts will seek them out instead of going in a straight line and odds are you will miss, and your attacks wont cause much.
You can slowly wittle down there HP and kill them. The only thing that you have to be careful of is that the Grandiers can Teleport ( I dont know if they can teleport over the barricade ) and the fact that they can hit you through the fence which is DEATH for low level characters, so once they start moving towards you take a step back and give it a few seconds ( just don't step too far or you will leave the map and have to go back and start completely over ).
Shamans can also stand up to the barricade and cast their Flame Totem over it and let it cause a little bit of damage. Just stay near the fence, back up when they come near, and cast the occasional Flame Totem along with some persistence and you can kill a level 47 Grandier for a hefty amount of XP.