God's Champion Achievement
Reach level 20 with any character.
Just as the title says, reach level 20 with any character. Level 20's at 190,000 EXP. That may seem like a lot, but really it isn't.
If you don't have it by the time you finish the story (I was only an 11) just replay the final level. If you defeat every enemy you can get anywhere from 15,000-25,000 EXP each run-through.