War Mace is a Primary Power Set for Brutes and Scrappers, and a Secondary Power Set for Tankers.
You are an expert with the big, two-handed mace. Not one for subtlety, you prefer the mace's direct approach to most obstacles. While anyone with the requisite strength can wield a mace in combat, you've mastered stunts and maneuvers that most could not hope to match. You attack with surprising speed, and often with such power as to knock your foes to the ground. You can sometimes even crush multiple targets at once!
A War Mace is a large, heavy weapon. You make a melee attack roll to hit a target with it, to which you add your Strength Modifier. You are also considered proficient with it, so you add your Proficiency Bonus to the attack roll. It deals base bludgeoning damage equal to 2d6 plus your Strength Modifier.
You are an unparalleled expert with your weapon. You are proficient with heavy two-handed melee weapons that deal bludgeoning damage. For the purposes of this Power Set, a War Mace is a maul (from the Dungeons & Dragons 5th Edition Player's Handbook).
You can also use your Action to make special maneuvers with your War Mace. You can use Bash, Pulverize, and Jawbreaker at 1st level. You can use Clobber at 3rd level if War Mace is your Primary Power Set and at 8th level if it is your Secondary Power Set. You can use Shatter at 10th level if War Mace is your Primary Power Set and at 14th level if it is your Secondary Power Set.
Starting at 2nd level if Battle Axe is your Primary Power Set or at 6th level if it is your Secondary Power Set, you can take a moment to focus your senses. Roll at least one Endurance Die. You can add the result to every War Mace attack and damage roll you make until the end of your next turn. Using this feature does not cost an Action but you can only do it on your turn.
At 7th level if War Mace is your Primary Power Set or at 11th level if it is your Secondary Power Set, you can swing your War Mace around you in a circle. Each creature within 8 feet of you must make a successful Dexterity Saving Throw or take 4d6 bludgeoning damage and be stunned until the end of its next turn. If the Saving Throw succeeds, the creature takes half damage but is not stunned.
You can use Crowd Control at 12th level if War Mace is your Primary Power Set or at 15th level if it is your Secondary Power Set.