earth mage is useless against skeletons.
Again with the "Is useless" arguments.
Fossil Strike and Fissure.
I don't understand why enemies don't have teleportation skill. I don't understand why mages can't teleport themselves. I don't understand why fire mage is as vulnerable to fire as a ranger.
Because you are bringing assumptions into it... and not even basic assumptions.
FFT does not give mages resistance to magic except that they have higher magic resistance stats... Which DOS2 does as well.
Mages do not teleport themselves because you do not have the teleport move they specifically get Netherswap. Nor have you put a point into Marskmen to get their version of teleport.
And many enemies do have a teleport skill of some form.