It's encouraged to mix and match your characters for every playthrough if you desire to play with new hero traits. Unfortunately, it means you have to create a new character to use those traits since hero traits cannot be changed mid-game. Hero traits are treated like new character classes think of them as subclasses within the main character class. Some hero traits can also be purchased using Hero Emblems in the subsequent season. You can unlock more hero traits from the paid Boon system, in-game achievements, and Hero Shop.
