Player's Handbook
Those who emulate the archetypal Battle Master employ martial techniques passed down through generations. To a Battle Master, combat is an academic field, sometimes including subjects beyond battle such as weaponsmithing and calligraphy. Not every fighter absorbs the lessons of history, theory, and artistry that are reflected in the Battle Master archetype, but those who do are well-rounded fighters of great skill and knowledge.
3rd-level Battle Master Feature
At 3rd level, you gain proficiency with one type of artisan's tools of your choice.
3rd-level Battle Master Feature
When you choose this archetype at 3rd level, you learn maneuvers that are fueled by special dice called superiority dice.
Maneuver save DC = 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice)
For a full list of Battle Master Maneuvers, see here.
7th-level Battle Master Feature
At 7th level, you learn two additional maneuvers of your choice.
7th-level Battle Master Feature
You gain another superiority die at 7th level.
7th-level Battle Master Feature
Starting at 7th level, if you spend at least 1 minute observing or interacting with another creature outside combat, you can learn certain information about its capabilities compared to your own. The DM tells you if the creature is your equal, superior, or inferior in regard to two of the following characteristics of your choice:
10th-level Battle Master Feature
At 10th level, you learn two additional maneuvers of your choice.
10th-level Battle Master Feature
At 10th level, your superiority dice turn into d10s.
15th-level Battle Master Feature
At 15th level, you learn two additional maneuvers of your choice.
15th-level Battle Master Feature
You gain another superiority die at 15th level.
15th-level Battle Master Feature
Starting at 15th level, when you roll initiative and have no superiority dice remaining, you regain 1 superiority die.
18th-level Battle Master Feature
At 18th level, your superiority dice turn into d12s.