There was a war in another solar system, Here in this solar system was a planet of people with powers given to them by the gem of creativity in the center of their planet. The other planets have a council where they all agree that's its best to destroy the planet because their scared of them, a worm hole on the outskirts of this solar system leads to the solar system of where the story takes place, leading a whole bunch of the super powered rocks on a head on course to multiple planets including earth, where it erodes in the atmosphere and dissolve landing on people becoming what humans call frankensteins
The dust can bestow basic powers like flight, ice, fire and stone etc., but it can also give weapons and suits of armor, as well as weapons that are alive in some instances, like having a katana that has bear abilities built in, there's also a chance they'll turn into a steins which is a brainless zombie like monster, when they turn they develop stitching in different patterns or colors on their faces, symbolizing their turn away from humanity.
As soon as they acquire these powers, weapons or armors they become a different race called Frankenstein and an investigation team made by the military to hunt them down has been made called Special Unit Franks, these people can kill the Frankenstein and steal their weapons or abilities the way they use their ability is by tattooing themselves with the users blood they want to get but that's with the powers, the weapons is simplistic enough as them picking it up off the body but it can take control of them if not compatible they can go berserk just like a person infected with the dust they can turn stein.
There is a sub race that comes later in the story because of a mutation in the stein that causes them to become smarter and start to eat humans to evolve similar to how hollows evolve from eating other hollows, these stein can eat humans other stein and also frankenstein's to evolve a True Frankenstein similar to the book version with stitched body parts but human like at the same time, they have boosted attributes and have abilities or weapons just like the normal Frankenstein, this leads to the Treaty arc where the franks sees these true Frankensteins as bigger threats and wants to make peace with the frankenstein to destroy the true Frankenstein which leads to the first war arc.
The stein even after transcending to a true Frankenstein still have to consume 90lbs a month to stay alive and normal food make them sick and taste disgusting, while not being fully fed the true Frankenstein re in a weakened state and are more vicious, frankenstein have to eat human flesh to stay alive aswell but only 30lb a month to keep the hunger at bay and they can't eat normal food, if they don't they'll turn go into a berserk hungered state and kill any human they can find.
There is groups compromised of 3 franks nd three squads can have up to 6, there is also a junior unit that act as the normal troops and don't get frank weapons or abilities until they rank up to make their own team, the team with the most huyokai's killed or captured gain points and get rewards such as food, money, and a place to stay for exchange for their duty as a frank, they have houses on a property that house each member of the squad, Depending on the higher ranking squad is the better rewards and pay you get so that's why most of the members of lower squads are more desperate, The number one squad in the frank unit is nicknamed the Knights of the Round Table, because of all 6 of their franks being very strong and unique.