Sumo Training
At 3rd level, you gain advantage on Strength (Athletics) checks and saving throws to resist being pushed or knocked prone. Additionally, your unarmed strikes deal additional damage equal to your proficiency bonus.
At 3rd level, when a creature within your reach misses you with an attack, you may use your reaction to attempt to grapple, shove, or trip that creature.
Sumo Technique
At sixth level you can now crush a prone enemy under your weight sacrificing attacks to deal Str + Con + Wis mod damage per attack not taken this damage ignores DR.
Your mastery of sumo wrestling allows you to seamlessly combine grappling and strikes. When you successfully grapple, shove, or trip a creature, you may use a bonus action to make the creature make a str save or be knocked prone until the end of your next turn. Creatures that would be immune to being knocked prone are not immune to this.
When you succeed on a Strength (Athletics) check to grapple or shove, you may treat the result as a natural 20 for the purposes of contesting checks against that creature on your next turn.
Sumo Focus
At 10th level, you can use a bonus action once per short rest to enter a Yokozuna's Fury state, which lasts for 1 minute. While in this state, you gain the following benefits:
You have advantage on all Strength checks and saving throws.
You gain resistance to all damage, except psychic damage. Additionally, when you take damage from an attack, you can use your reaction to make a Strength saving throw (DC equal to the damage taken). On a success, you negate the damage entirely.
At the start of each of your turns, you gain temporary hit points equal to your Strength modifier + your Constitution modifier + your Wisdom modifier.
If a creature is prone you can spend your action to jump on top of them keeping them prone until they are able to escape from your grapple.
Unbreakable Calm
At 14th level, you can use a bonus action once per short rest to regain hit points equal to your Sumo Wrestler level plus your Constitution modifier.
At 14th level, you gain proficiency in Wisdom saving throws.
Send Flying
At 18th level, at the end of your turn, each creature you hit with an unarmed strike is launched 20 feet in a direction of your choice for each unarmed strike you hit them with.
When a creature you launch collides with another creature or object, they take bludgeoning damage equal to your Strength modifier + your proficiency bonus.
Both the creature and the target they collide with must make a Strength saving throw (DC equal to 8 + your Strength modifier + your proficiency bonus) or be knocked prone