You can unlock badge pieces, characters, and skins by progressing through each Monster’s Character Mastery. This forces you to use all of a Monster’s unique abilities to progress to the next level. Character Mastery is something that should be completed passively, as actively trying to complete these challenges could cause you to take a few losses. You can find each Monster’s specific Character Mastery in its respective section.
Mastery Rewards
Whenever the Character Mastery objective is met for a skill, you are automatically granted a small percentage bonus to that skill. To advance the skill again, you must complete the mastery challenge for the three other skills. Doing so unlocks a badge, a new character, or a skin, depending on the level achieved.