The Mutable Patron

Your pact is not a bargain, but a bond.

A doppelganger tried to end and replace you, some interference during its attack has fused its essence with your very being.
Your patron’s consciousness resides beneath your skin, granting elements of its abilities.

Whether you view your patron as parasite or partner, its power is now intertwined with your own.

Those who walk as a mutable tread a thin line between self and other, flitting between humanity and the writhing truth beneath the surface.
Each day you wake wondering, where do you end, and where does it begin?

Level 3: Mutable Form

Living Weapon:
As a bonus action, you can reshape one of your limbs into a natural weapon of your choosing;

• Blade Arm: Melee weapon 1d8 slashing [Finesse]
• Maul Arm: Melee weapon 1d8 bludgeoning
• Spike Barrage: Ranged weapon, 1d6 piercing, range 30/90 ft, counts as thrown (you can regrow spikes instantly)

[These weapons count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks.]

Mutable Flesh:
As an action, you can alter minor aspects of your appearance (hair length, facial features, voice)
You can maintain this indefinitely until you change again. 

Level 3: Doppelganger Spells

The magic of your passenger ensures you always have certain spells ready; when you reach a Warlock level specified in the table, you thereafter always have the listed spells prepared.

Fiend Spells

Warlock Level	Spells
3	Suggestion
5	Stinking Cloud
7	Blight, Hold Monster
9	Insect Plague

Level 6: Malleable Form

Echoes: As an action you can focus your senses on one creature you can see within 30 feet, for 1 minute:

• You gain a vague impression of its emotions and recent memories, enough to mimic its tone, posture, or behaviour.
• You have advantage on Charisma (Deception) and Wisdom (Insight) checks made interacting with the creature (or with any other creature where the check is about the target).
• You can use this feature a number of times equal to your Charisma modifier (minimum of once).
• You regain all expended uses when you finish a long rest.

Adaptive Flesh. With better control of your transformational abilities, you can use your reaction to momentarily morph your body to resist harm.

• You sense incoming damage and are able to adjust your skin to better defend against it, you have resistance to that type till the end of your next turn.
• You can use this feature a number of times equal to your Charisma modifier per long rest.

 

 

Level 10: Simul Fortis: Awakened

As a bonus action you can allow the doppelganger to mutate your form for 3 turns.
When you do so, your body bulks and warps;

While transformed:

• You gain temporary hit points equal to your Warlock level + Charisma modifier.
• You gain more powerful living weapons
• You have advantage on Strength checks and saving throws  

When the transformation ends, you gain one level of exhaustion.
You can use this feature once per long rest.

Level 14: Simul Fortis: Perfected

You have mastered fully fusing with the doppelganger for 4 turns.
When you use Simul Fortis you can choose to take the 'Perfected Form', a larger, stronger transformation changing your size to Large.
During the transformation you gain;

• Even stronger biomass weapons, one slashing and one bludgeoning 
• Resistance to bludgeoning, piercing and slashing damage
• One additional biomass weapon attack per turn
• Saving Grace: The first time you drop to 0 hit points while transformed, you instead remain at 1 hit point and the transformation ends (once per transformation).

You gain one level of exhaustion after your transformation, increased to two levels if you drop to 0 hit points and remain at 1 hit point