If you want to go in order of difficulty, Warrior --> Conjurer --> Wizard. Warrior gets no magic, but gets high HP, strong weapons and armor, and unique abilities that give them some advantages when fighting magic. Strong, fast, and good for just hacking and slashing your way through everything. Conjurer gets strong bows and some good spells, as well as creatures to fight in their stead along with some good healing spells and light armoring. Wizard though gets very little armor protection and HP, so there's a lot of running and casting as a wizard sometimes, though there are some defensive options that can help if played right.