Acrobatics and armor generally seem at odds. However, for those with the aptitude and drive to perfect their technique, the additional weight and momentum can be wielded to devastating effect both in bypassing lines of defense and landing powerful blows. Whether leaping and bounding, flipping and spinning, or bouncing around like a pinball, the Armored Tumbler rushes about the battlefield, hitting targets who think themselves safe while avoiding retaliation and disrupting planned defenses. 

Armored, Athletic and Acrobatic

Accomplishing feats of strength and agility on the battlefield, you wear armor as ably as any warrior, while proving yourself a dangerous and deadly asset. You gain proficiency in the Athletics skill and Medium Armor and Shields. You also gain expertise in Acrobatics. If you already had expertise in this skill, you may apply expertise to one other skill you are proficient in.

Careening Strike

Ducking, rolling, weaving, tumbling, charging, flipping, leaping across the battlefield you evade opportunity attacks and strike a distant target who thought themselves safe. When taking the Dash action (or bonus action from Cunning Action) opportunity attacks against you are made at disadvantage. Additionally, if you take the Attack action using a melee or thrown weapon you are proficient with after moving more than your walking speed, you may add your Acrobatics proficiency modifier instead of your attack bonus and apply your Sneak Attack bonus to damage on a successful hit.

Bypassing Strike

Beginning at 9th level, your ability to flip, roll, squeeze and tumble past opponents while delivering devastating damage is bewildering. On your turn when Dashing, you can move through opponents' spaces as though it were difficult terrain, but cannot end your movement in an opponent's space. An opponent whose space you moved through cannot take opportunity attacks against you until after its next turn. As a reaction, you may attack one opponent whose space you moved through, applying your sneak attack bonus to damage on a hit. You could possibly land two sneak attacks in the same turn,  even on the same opponent. 

Rebounding Strike

At 13th level, after delivering a devastating blow against your opponent, you add insult to injury by effortlessly springing away again to strike another target. Following a successful Careening Strike, you may move an additional distance away from the opponent, up to to half your walking speed, and make another such attack against a different opponent, applying your Acrobatics skill modifier in place of your Attack Bonus and adding your Sneak Attack damage on a successful hit. You cannot make more than two Careening Strike attacks on your turn.

Supreme Tumbling

When you reach 17th level, your tumbling abilities have reached a point where you can roll through a horde of enemies, moving and striking seemingly at random. As an action, you may attempt a melee attack against every opponent whose space you moved through (counting as difficult terrain), without risking opportunity attacks, but cannot attack the same opponent more than once regardless of how many times you move through its space. You do not use your Sneak Attack bonus for any of these attacks. Once you use this ability, you cannot use it again until you complete a Short or Long Rest.