Cogs are mechanical machine men given minds, souls and life by their creator;
A great Cleric of the life domain, “Malchiore”. He saw the empires of man as a corrupted vehicle of death, and vowed to undo the lives that his people had taken, by creating new life.
He fled from his city, raised an island from the sea (Known as “The site”) and used mechanical parts to create thousands of statues. Then, sacrificing the remainder of the unnatural long life given to him by his deity, he imbued the statues with souls of their own. These statues are the Cogs.

Cogs often worship Malchiore as a God and can draw on his strength to perform miracles. They also feel indebted to humans for their lives and thus, mostly serve humans. The majority are treated as slaves therefore, fighting in the human armies, or working as servants in their homes. Conversely, Cogs view humans as status symbols, and will dress in human clothes, even though they don’t need them, and will often make modifications to their bodies to appear more human (porcelain masks, coils for hair etc).

As mostly slaves, no one will teach Cogs the ways of magic, and almost none have ever shown any magical prowess. They tend to rely on religious power to cast spells rather than the arcane, although they can use magical items that they collect.

Cog Traits

Ability score Increase

Your Constitution increases by 2.

Age

Noone knows how long cogs will live as they are all the same age, and cannot reproduce. The only ones to die so far have been through violence.

Alignment

In their worship of Malchiore, most Cogs tend to be of a lawful disposition, and are predominantly good, but many "stray from the path".

Size

Cogs are generally all very similar in build and are roughly 6 feet tall before any modifications they make to themselves.

Speed

Your base walking speed is 30 feet.

Inorganic immunity

You do not need to breathe and therefore are immune to drowning and breath-induced gas attacks. You are immune to all poisons and never need to eat or drink and therefore cannot be conventionally exhausted. You are also immune to ghoul paralysis and have advantage against saving throws to put you to sleep.

Repairs

You do not need to sleep, or eat, leaving rest to be non essential to you. However, you do need to repair yourself regularly, as you tend to weather away joints, gather rust or fill with detritus on your travels. Your repairs usually take 4 hours, and leave you in as good condition as a human would over 8 hours of sleep.

Languages

You can speak, read and write Common, and Binary; a shorthand used by Cogs to convey messages faster than most written languages.

Mechanical proficiency

If firearms are prevalent in your D&D world, you will want to make Cogs proficient in those. If not then Crossbows will be a fitting replacement.

Subrace

Cogs are generally divided into two main subgroups; the Brass Cogs, and the Porcelain Cogs. Brass Cogs are usually more religious in nature, desiring to maintain their appearance as Malchiore made them; simple, brass, copper, steel and wooden frames, with little use for clothes or wanton violence. Porcelain Cogs tend to stray from the religious path more readily and embrace human culture, tending to weld masks onto their faces to appear more human, and sometimes undergoing extensive modifications to appear to have a human gender. There are obviously categories in between, but depending on which you choose, you gain the following benefits:

Brass Cog

Ability score increase

Your Wisdom score increases by 1.

Artificer's cunning

Whenever you make a Wisdom (insight) check to determine how a mechanism or trap might work, you can add twice your proficiency bonus instead of any proficiency bonus you normally apply.

Porcelain Cog

Ability score increase

Your Strength score increases by 1.

Milk of human kindness

You have spent so much time serving or generally in the company of humans, obsessed with their motives, that you have picked up some of their behaviors. You gain proficiency in two skills of your choice.