At 3rd level, when you choose this archetype, the mutation of your body progresses further and goes beyond the mere evolution to deploy tools of destruction or protection and allows you to quickly adjust to issues you face on the fly.
These quick mutations are taxing and they are represented by a number of mutation surges. Your underworld monstrosity level determines the number of mutation surges you have, as shown in the Mutation Surge column of the Underworld Monstrosity table. You can spend these surges to fuel various class features. You begin knowing three of them: Mutating Flurry, Chaos of Limbs and Weird Movement. You learn more as you gain levels in this class. When you spend a mutation surge, it is unavailable until you finish a long rest, at the end of which your body regenerates its rapid response mutation capability.
Immediately after you take the Attack action on your turn to attack with a mutation attack, you can spend 1 mutation surge to make two mutation attacks as a bonus action.
Chaos of Limbs
You can spend 1 mutation surge to take both the Disengage and Dodge action as a bonus action on your turn, tearing off a twitching, monstrous mutation to cover your retreat.
If you do so, you sacrifice one of your deployed weaponized evolutions, which is destroyed as you retreat. This weaponized evolution cannot be used again until you have completed a long rest. This inflicts no damage upon you.
You can spend 1 mutation surge to take the dash action as a bonus action on your turn, doubling your jump distance for the turn.
Highly Mutagenic Arsenal
At 6th level, you can, as a bonus action, spend any number of mutation surges to re-assign your weaponized evolutions. You expend a number of mutation surges equal to the number of evolution points you wish to reassign and may assign them anew, as though you had completed a long rest. Additionally, your mutation attacks now are treated as magical weapons. You receive +1 to attack rolls and damage rolls with your mutation attacks. Additionally, when successfully striking a creature with a mutation attack that has been customized with the energy mutation customization, you may spend 1 mutation surge to add +1d6 to the damage the attack causes, with the damage type corresponding to the damage type chosen via energy mutation. You may spend a maximum of mutation surges this way equal to your proficiency bonus per turn.
Highly Mutagenic Form
At 11th level, you can, as a bonus action, spend any number of mutation surges to re-assign your body evolutions. You expend a number of mutation surges equal to the number of evolution points you wish to reassign and may assign them anew, as though you had completed a long rest.
Hunter in the Dark
Beginning at 17th level, you can use your action to spend 4 mutation surges to become resistant to all damage types but radiance for 1 turn. Additionally, all creatures in a 10-foot cube originating from you must make a Wisdom saving throw against your mutation save DC. The creatures that fail their saving throw are frightened by you for 4 rounds.
Underworld Races and Classes © 2017 AAW Games LLC; Designers: Thilo Graf and Mike Myler