Bone Jugger

A combination of bones, sinew, and technology, merged together though Technowizardry into disturbing autonomous constructs.
Bone Jugger is the name people have given them. They have no name of their own and whatever names their creator gave them have passed with the creator.
They do not speak, they do not negotiate. They each have one purpose but all are capable of defending themselves. The scouts scout for sources of raw materials. The harvesters consume corpses and convert them into raw materials. They can also strip machines and take all manner of technology. The Mules carry all the raw material and can pick up materials they come across as well. There are two types of Wardens, melee and ranged. Finally the Hens can replace losses by assembling new juggers on the spot.

Mechanics & Inner Workings

Using skeletons for their primary structure, mechanical components are used to link and move their various pieces. Their mechanical power is provided by digesting raw organic materials and also by burning fuel oil, which it seems to reserve for times of maximum demand. The bones themselves appear to be spiritual batteries for the necromantic energy that gives them their autonomy.
Only the harvesters are capable of refining organic material into the slop they all use for fuel, but they are all capable of sucking up fuel oils when encountered. It seems they can burn any oil.

Manufacturing process

Only the central manufactory can perform the processes necessary to create an autonomous bone jugger. It is comprised of large tanks of raw biological materials and gravity fed bins of assorted technological bits. Powered by necromantically bonded spiritual energy, it should be capable of operating on its own for centuries at full capacity.
The inner workings are a mystery and so far only the original creator was capable of unlocking the secrets of making Bone Juggers.

History

It was only a matter of time until someone came up with this idea.
One works with the materials available, and the apocalyptic battlefield was awash with bones of the dead, from those of fallen humans to extraterrestrials and even supernatural monsters.
One promising necromantic Technowizard found a way to combine all those bones with technology to create autonomous machines. She built machines for combat, of course, but she was most proud of the machines she made to perform chores and help with everyday life.
She called them her "Helpers." She was only able to make a few because the process was so time and resource intensive. There was a Butler that took care of domestic chores and received visitors. There was a Gardner that maintained her landscaping with such meticulous precision it got the attention of powerful mages far and wide. And, of couse, there was her Warden to defend her and her home. She was building her second warden when it occurred to her she could automate the process. Some think the idea came to her in an epiphany, but there are those who think some more nefarious intellect was leading her to this path.
It took her decades to build, but she finally came up with an assortment of Helpers that, together, were capable of making more. During this time she finally finished her second warden, one that was equipped with ranged weapons.
The helper self-productoin effort consisted of scouts, harvesters, mules, and of course, the central manufactory. She even created something she called a Hen, that was able to carry an assortment of prepared parts from the manufactory and assemble new helpers on the spot. She would send a Hen out with her resource expeditions to make up for any losses they accrued.
With this arrangement she was ready to take orders for helpers, and she began to advertise. The demand was immediate and outstripped per capacity. In desperation, she instructed her manufactory to make its own corpses for harvesting. Hers was the first corpse it created.
What followed was a methodical slaughter of all living vertebrates that continues to this day. Helper resource expeditions can be found throughout North America east of the mississippi river.

Significance

Only one person has ever unlocked the secrets of creating Bone Juggers and she is dead. These creations are so impressive, however, that the powers of the The Federation of Magic have declared the manufactory off limits and to be preserved at all costs until someone else is able to reproduce the feat.
Until that happens, the countryside will have to deal with the constant nuisance of helper resource collection teams.

Rarity

There are a few long-ranging Bone Juggers, but most can be found in and around their homesite somewhere in the The Federation of Magic.