Stone Fist

The Stone Fist
The stone fist seeks to balance out their blind fury and peerless strength with the monastic training of a monk. Which is to say really, they learn to hit things hard with their fists instead of a big honking weapon.

Earthen Fists
The stone fist's hands are toughened with a long regimen of striking stone with their bare hands! They have awful, awful nails. Just awful. At 8th level, the stone fist gains a ki pool (as the monk power) equal to one-half their level. Their unarmed damage becomes 1d8, and whenever they hit with an unarmed or weapon attack, they can make an unarmed attack as a bonus action. The stone fist's unarmed damage increases to 1d10 at 13, and 1d12 at 18. Additionally, the barbarian's Unarmored Defense feature is modified; the stone fist now has an Armor Class of 10 + Constitution Mod + Strength mod while not wearing armor or using a shield. They gain the following abilities for spending ki (stone fist ki DCs are 8 + Strength mod + Proficiency Bonus):
 * They can spend 2 ki to emulate the Flurry of Blows feature.
 * They can spend 1 ki while raging to reduce damage dealt to them by their Constitution modifier until the end of their next turn. However, they can only use this reducion on one attack or effect per turn.
 * When they hit with an unarmed attack, they can spend 1 ki. The hit enemy must make a Dexterity save or be knocked prone.

Stone's Mettle
The stone fist is not only strong, but durable as well. They almost never get drunk. At 13th level, when subjected to an effect that allows the stone fist to make a Strength or Constitution save, they suffer no effect on a success, and if they fail, they suffer a reduced effect, if any. Otherwise, the full effect goes through. Additionally, once per turn when they hit with an unarmed attack, they gain THP equal to their Constitution mod.

Mountain Slayer
The stone fist's strength is legendary, it is said they can split open a mountain if they are along far enough in their training. Of course, nobody has ever actually seen it. At 18th level, the stone fist can spend a minimum of 3 ki points when they hit a creature with an unarmed attack to add 1d4 damage per ki expended. In addition, the target creature must make a Constitution save. On a failure, it is knocked prone and stunned until the end of the stone fist's next turn.