Great Machine Patron

The ancient voice rumbles through the bunker, its whirring and clicking binary speech grating against your skull. It's like it claws digging in through your very soul, infecting your senses with its presence. “Come to me.” A chill runs up your spine as you understand its speech. “Bond with me, free me from my cage.” Against your will, you creep forward, deeper into the foggy bunker, closer to the voice. The metallic tasting air fills your lungs, and the voice grows louder. “BECOME MINE!” You awake from the nightmare, breathing heavily and sweating a puddle underneath you. Then the speech begins anew.

Artificially Enhanced

Starting at level 3, you have bonded, at least partially, with your mechanical patron, having them partially entangled with your mind and flesh. You gain an additional reaction which can be used once, and regain the use on a rest. Additionally, you are now resistant to Lightning damage, and your mind cannot be read by magical means.

Machine Bonded

Also at level 3, the bond of mechanical and biological enhances both parts, to make something greater than the whole. You know Binary, and gain expertise in the Hacking and Computer skills, and can use your Charisma modifier for checks in these skills. Additionally, you can roll one additional hit die for free when you take a short rest, you can do this once, and regain the ability to do so after a long rest. (In a non-sci-fi setting, Hacking and Computer skills could be replaced by any non-physical skills, or any Int/Wis skills)

Beyond the Limits of Flesh

Starting at level 6, as the tendrils of the machine dig deeper into your body and soul, they grant you new power beyond that of the weak and flimsy meat of your natural body. You can use Charisma in place of Strength, Dexterity, or Constitution for any roll that would normally use these modifiers, a number of times equal to your Charisma Modifier. You regain ½ your spent uses of this ability, rounded up, on a short rest. You regain all uses on a long rest. Additionally, whenever you deal Lightning damage to an enemy, you can force them to make a saving throw against your Spell Save DC, or become Infected with nanomachines for one minute. While infected, a target takes an additional 1d6 lightning damage any time they are hit with an attack. Only one creature can be Infected in this way at a time.

Instant Recharge

Starting at level 10, your natural processes and capabilities that allow you to rest and heal have been enhanced by the machine that slowly consumes you. As an action, you can immediately gain the benefits of a short rest. You can do this once, and regain the ability to do so on a long rest.

Upgrade

Finally, at level 14, your body and being have been fully enhanced, improved, made better by the machine you have now become, leaving you a being of soul and machinery. You become immune to Lightning Damage, can deal 2d6 lightning damage on an Infected creature as a bonus action, and when an Infected creature dies, you can use a reaction to cause them to explode in a cloud of electricity, dealing lightning damage to any creature within 15 feet that fails a dexterity save against your Spell Save DC, equal to 3d6 lightning damage, or half as much on a successful save. Additionally, your movement speed is now doubled, you can use your Charisma Modifier for all jumps, your Jump distance is doubled, your carry weight is doubled, and your creature type is now Construct, if it wasn’t already.