Ember-IV

Ember-IV was a biological weapon developed by BioCorp. The virus was engineered to be nearly undetectable in the human body and possessed a "delay trigger" that set it off at a random time, ensuring it would be passed on to its next target before its host died.

In its incubation period, it could be transmitted by exhalation, making it an aerosol and extremely contagious. It would cause rapid neurological collapse by gradually accumulating toxins in brain tissue, with victims reporting that "time slowed down" before they died, making their deaths excruciatingly drawn out and painful. Its accidental release was near Nagasaki, Japan resulted in the Nagasaki Outbreak, a local epidemic which killed nearly 2,700 people.