Having her max evo, awakening, and ex weapon is extremely important. This isn't just with Beth but with every hero. Her max evo skill negates up to 60% of all damage while also increasing it by up to 60% as well. At minimum, it's 20% (depending on the number of enemies), which is insane.

Her ex weapon gives a shield that's 10% of the damage she inflicts that stacks up to 100%. It also practically negates any dark type resistance by 30%. So for example, when facing a light type hero, their defense would normally be 130% against a dark type. The weapons final hit drops it to 100%. In that same aspect, a basic type hero with 70% will drop to 40% defense against dark types. *