One of the easiest ways to level up if you're having problems with the Fire Guardian and the World's Saviours is to go to the Earth Temple. In the Earth temple, there are four doors in the main room. Each door leads to a room with a puzzle that shows a pattern that you have to repeat. Instead of repeating it, mess up and you'll have to fight a "Churlish Golem." Simply defeat it and keep fighting the Churlish Golems until you need to heal. Use Mardek's warp skill to leave the Earth Temple, heal, and then go back and do it again. It takes a bit of time, but it gives good exp.
This game is a marvel and I love it. Problem is, there's an abundance of glitches in the travel system. I actually was fighting a bunch of crates named Benjamin. Still 5/5
Same here Ben. Some idiot turned off the computer after I said not to and I lost my progress. I was expecting about a few thousand dollars when I woke up this morning and was disappointed.