Path of the Mutability
Some barbarians call upon bestial rage. Others channel ancestral power. But you? Yours is the blessing of a forgotten behemoth - a primal essence that shifts your size with your fury. By embracing physical instability, you become an unpredictable force on the battlefield: a stalking gnat, a crushing titan, or something in between.
Mutability (3rd Level)
When you enter your rage, you may choose to grow larger or smaller, shifting your size by one category (e.g., Medium to Large, or Medium to Small). You remain this size for the duration of the rage and cannot change it again until the rage ends.
Your equipment resizes with you. You cannot exceed Huge size or drop below Tiny. If there is insufficient room to occupy your new size, you take the largest possible form without squeezing.
While Enlarged:
Your melee weapon attacks deal +1d4 bonus damage.
Your reach increases by 5 feet.
You have advantage on Strength checks.
You may Shove or Grapple as a bonus action once per turn.
While Reduced:
Your AC increases by 1, and your speed increases by 10 feet.
You have advantage on Dexterity (Stealth) checks and Dexterity saving throws.
You may move through hostile creatures’ spaces as if they were difficult terrain.
Your weapon damage is reduced by one die size (e.g., d10 → d8). Damage cannot be reduced below 1d4.
Increased Mutability (6th Level)
While raging, you can change your size (Enlarged or Reduced) as a bonus action once per turn. You also gain the following enhancements based on your current size:
While Enlarged:
When you hit a prone creature with a melee weapon attack, it takes an additional 1d6 damage.
You can move through spaces one size smaller than you without squeezing.
While Reduced:
You ignore difficult terrain caused by creatures.
Opportunity attacks against you are made with disadvantage.
Enhanced Mutability (10th Level)
You can now shift up to two size categories while raging (e.g., Medium to Huge or Medium to Tiny).
While Enlarged:
When you reduce a creature to 0 hit points with a melee weapon attack, you may move up to half your speed as part of the same action.
While Reduced:
You gain a supernatural leap:
Long Jump: You can leap a number of feet up to 4 × your Strength score, with no movement required.
High Jump: You can leap up to (3 + your Strength modifier) × 4 feet vertically.
Perfected Mutability (14th Level)
Your form becomes fully fluid. While raging, you may change your size to any category from Tiny to Huge. Whenever you increase your size by one or more categories when entering a rage, you may choose to burst outward with explosive force. You can use this effect once per rage.
If your new size would cause you to burst from a container, structure, or creature's space, each affected target must make a Dexterity saving throw (DC = 8 + your Proficiency Bonus + your Constitution modifier).
On a failed save, the target takes bludgeoning damage equal to: (2 × your Rage Damage) + (2 × your Proficiency Bonus) + your Constitution modifier, and may be destroyed or slain at the GM’s discretion.
On a successful save, the target takes half damage and remains intact.
While Enlarged to Huge:
Your melee weapon attacks deal +2d6 bonus damage.
You count as one size larger for purposes of lifting, carrying, pushing, dragging, grappling, and shoving.