You play through the tutorial and chapter 1, and it's easy. Then you play through chapter 2 and you start really having to have fire magic, so you create fire mages, but they're level 1, and you're level 6, so you go back and play the tutorial a few times, and maybe the first few levels, and it's super tedious, but the main characters learn Fire and that's enough to push through.
You then clear chapter 3, and chapter 4, and the game drops a fire world on you, so it's time to do all of that again, but now you're level 13, and your brand new ice mages are still level 1.
I can only imagine this stuff getting worse and worse as the game proceeds. I do know that you can use team attacks in order to have a low level character deal 1 damage, his mentor deal the rest of the damage, and the low level character gets credit for the kill. However, if something goes wrong there and the target gets a counterattack, the low level character will get one-hit KO'd.
Also, this gets in the way of the whole reason why you wanted to make that character in the first place: getting your front-runner to learn new skills. The ice mage can team attack with the mentor, or the mentor can borrow magic from the ice mage, but you can't do both at the same time.
Chapter 3 makes you realize that the item world can be a good way to turn a cheap item into a decent grind that you haven't seen before, but when your mages die in B3, there's very little reason to push forward; early exit items are expensive and rare.
Am I doing this wrong? Was I supposed to grind my fire mages to the point where the could transmigrate to ice mages instead? Doing that still drops them to level 1.
How can I get new characters, or at least new classes, to become efficiently combat-ready in my party? If your answer doesn't apply to the early game, that's okay, just say so.