This basically gives more attack speed, faster movement, and resists
Bellato: I'll start with Bellato, since I like them more as they're cute and stuff. You'll start at level 1, duh, and then at level 30 you can change knight gold class. These changes of classes are for specializing the characters. There are different routes to take. At level 40 you change again.
Now, firstly is the Warrior. This is your close ranged fighter. They have the highest defense, and that doubles with a shield along with block rate.
And yes, blocks work against magic. They can do great damage with two handed weapons, but then they are within range of a lot of people so they can die quickly that way. This is why most will go Sword/Shield.
Along with going Sword/Shield many will use ranger armor. This basically gives more attack speed, faster movement, and resists. This resists also counter the -20% all elements that shield gives and the lowering defense using defense tails (in a new update each +defense telic lowers all resists some).
While this means more training to raise your ranged PT, it is worth it if you want to be strong. Now at level 30 you have two choices, either offensive as Commando or Defensive as Miller.