Into the Cold, Hard Black

A sci fi setting where warp travel crosses into a seemingly empty sub-dimension but occasionally results in something crossing over. This "infection" takes over people, driving them mad and fusing their bodies with machines. These techno-organic mosntrosities can merge with existing technology and bend it to their will. Their blood becomes caustic. They do not feed on the living, they infect them with their ichor and hold them until they lose their selves to the "infection." Some are immune to the infection, they must prevent the infection from reaching the rest of humanity... Or maybe they are the infected ones...

The "heroes" have their minds broken by the jump. They reinterpret everything in the context of the warp sickness mythos. They have lost their minds and may be able to recover if captured, but those that are not will fight tooth and nail to "survive" and "save" humankind from "infection." Zombies are people that are not warp sick, so they can do everything a normal person can do, but it is always interpretted by the gap sick as some sort of mutant techno-organic freakiness... Or maybe they really are infected by something from beyond the stars with inscrutable motives.

Evil Eyes

A strange and virulent toxin is spreading in the world. It drives people insane, rendering them mad with blood lust with a disturbingly hostile intellect. The military was helpless, but not because of lack of firepower. When they set up a line to stop them, the news broadcast showed, briefly, that the bloody mist remaining from a badly shot person stayed in the air in a ghostly shape. It continued to march forward as the bits of human fell free and it could not be seen anymore. Shortly after, the military started to turn on each other. Some people report seeing a malevolent twinkle in the eyes of the crazed people, even in the dark but it hasn't be caught on camera yet.

The infection is actually a bunch of spirits/demons. I liked saying Anasazi but they could be demons or hungry spirits from another dimension. Either way, they like to ride bodies and propagate their species by fatally injuring and spiritually infecting others. They can pilot dead bodies or kill the living through essence damage and then pilot the empty body. Bits of life cling to their spirit matrix for a bit, making a recently blown away zombie spirit visible as a "creature" shaped cloud of blood and flesh. Their weakspot is their eyes. They are visible as "hungry and malevolent spirits" (described in whatever way might befit the ZM's setting) with twinkling as the seat of their soul. Characters with the Gift (available even if no powers are available; possibly required for at least one member of the Main Cast but not given to Supporting Cast) can see and sense the spirits at all times (maybe up to 10 yards per Per level). Voids are invisible to the spirits and their zombie hosts. The spirits are legion and rapidly consume and take over the spirits and bodies of their hosts. They are crazy strong, fast, and sense life like no one's business because they track the spiritual energy of people.[/spoiler]

Clarity of purpose. Clarity of conscience.