Samuel Kemp has developed a machine that makes him invisible. Using the ambient galvonic field generated by a city's Tessla Array, the device warps the perceptions of those around him. They can't perceive wearer if within the field of the effect (about a mile). This includes all senses - human brains are being manipulated to ignore the wearer with a base-level primitive meme directly beamed through the optic nerve. The machine itself is powered by the ambient energy and as such never need be turned off.

Unfortunately there are side effects and problems-

1. the field it generates causes physical corruption in the wearer at the rate of 1 point per week.
2. the godlike feeling of getting away with theft, rape or murder also tends to cause corruption - if the wearer commits immoral or illegal acts while wearing the device, they gain a point of corruption.
3. the device has no effect on non-humans, including the animate. Any brain other than a living Human one.

Plot Ideas-

1. Kemp has an accident and the device falls into the hands of a PC.
2. Kemp becomes an assassin and it is up to the PCs to stop him. This may entail luring him to an open location and targetting him from outside the effect of the field.
3. A sentient vampire kills Kemp and takes his device.