Doctor Helen Cooper was a famed Human scientist, who was most notable for her work with Imulsion. She ended mankind’s dependency on fossil and nuclear energy by perfecting the Lightmass Process, which allowed humans to turn raw Imulsion into cheap fuel and energy for Sera's cities.
Although Cooper’s findings were meant to benefit mankind, they eventually led to the Pendulum Wars. Imulsion deposits were concentrated in only a few of Sera’s nations, meaning that only those nations could harvest and process the prized substance. This ultimately led to a great power and wealth imbalance on Sera, forcing nations to be pitted against each other in a fight for existence that came to be called the Pendulum Wars.
- Main article: Pendulum Wars
With Sera now having an unlimited source of energy, the Era of Silence ended and was replaced by the era known as the Gold Rush. Many Imulsion miners had their lives drastically shortened as result of exposure to Imulsion, but this downside was seen as a necessary sacrifice to ensure Sera’s energy security. The health issues surrounding Imulsion would reappear a century later in the form of Rust Lung. The rampant speculation of Imulsion and the ever-increasing demand for the substance led to a major financial collapse and eventually to the Pendulum Wars, ending the Gold Rush era, This 79-year-long war left millions dead. The greed surrounding Imulsion was put on hold after Emergence Day . The Locust Horde would not ally themselves with the Humans of Sera, for they saw them as greedy and destructive, taking whatever they wanted by force. The Horde invaded the surface of Sera and fought against the Humans in order to colonize the surface and continue their fight against the Lambent.