Slumbering Matrix (Uncommon). You your character's race is changed to the Aberrant Entity. 

 Limb loss is a minor inconvenience. You can use an action to generate an "Aberrant Limb", and have up to two of them active. This can be done a number of times equal to half the characters level. 

Unarmed strikes become 1d6+str and have proficiency added on rolls to hit. If the user is hit with the spell shatter, he must make a constitution saving throw (Dm chooses the DC), to prevent one of these arms from shattering. 

Aberrant Drill: the user gains the mold earth cantrip, and can use a bonus action to convert one fists to a crude drill. When making an unarmed strike, he can opt to use piercing damage instead, and for each arm converted this way, the user gains 10 feet of burrowing speed.

Lending a hand: If a creature within 10 feet is hit with an attack roll, you can use a reaction to sacrifice an aberrant limb, giving them the benefits of a shield spell. After this, the limb is destroyed and a new one must be made.

Unarmed: For each missing arm, the player suffers -1 to any attack rolls, saving throws or ability checks reliant on the missing limb.

Notes: The Matrix replaces the heart of the user, forever bonding to their body and soul.