How do people level up so fast?

 Getting back to Victoria from places

• Mercedes can warp back to Elluel with a 30 minute cooldown. This is their link skill too, so you can give this benefit to any of your characters with a level 70 Mercedes.
  
• Kaiser and Angelic Buster get free warps directly to Pantheon with a 10 minute cooldown.
  
• Victoria: Nope.
  
• Orbis: Victoria is two minutes away by plane.
  
• El Nath: Orbis Tower. Two minutes away by plane.
  
• Ludibrium: Ride down to KFT, then to Aquarium, then to Orbis Tower, and back to Orbis. Two more minutes and you're there.
  
• Leafre: If you're here you can afford a 30k magic seed back to Ellinia.
  
• Magatia: Two minutes away by plane.
  
• Mu Lung: You can fly to Orbis, or go to Herb Town, then Aquarium, then Orbis Tower and Orbis.
  
• Ariant: Karcasa can warp you back to a random Victoria town for 10k.
  
• ANYWHERE if you like: Warp to NLC via Dimensional Mirror and take a subway train back to Kerning City. If you really want to. This generally takes longer.

Don't forget Lumi after 4th job ? or whenever you start teleporting to that girls house, you can use it anywhere without any cool-down and leaving it drops you off at Vic. Best class IMO for abusing Pantheon teleport.