POLISTES SULCIFER PARASITES (paper wasp parasite)

The parasites themselves are small, in the wild they're about the length of a football. Implanted in a human body they roll up to about the size of a grapefruit. Through humans, they extract nutrients, and facilitate a massive expansion in their ever-growing population, reproducing at high rates. They need humanity to keep up, so they increase human birth rates. Every human pregnancy results in at least twins, but often more. As a result most populations look startlingly similar.

A human infected by a parasite gains many positive traits. The only negative is a very short lifespan (average span is 35 years). The positives though, are myriad. Their physical endurance is far higher than normal, and they are bigger, stronger, and faster than unbaptized humans. Their creative ability is boosted far higher than normal. They can subsist on very little real nutriment. They become capable of extracting nutrients from the soil, from clay, literally eating dirt. They have techniques that allow them to bury themselves in rich soil if need be, and go dormant, extracting nutrients from the soil. If need be they can hibernate like this for several years with enough elan to keep them sleeping and dreaming. In a fight against an un-infected human, even the weakest parasitized human is extremely dangerous. They are more durable and resistant to physical injury. Damage to limbs and extremities heals quickly, and they can regenerate lost limbs. Any injury can be ignored that isn't a hit to the head or chest. They're impervious to bacterial and viral infection and all forms of cancer or autoimmune disease.