Sera (Gears of War)

Sera is a fictional planet from the Gears of War video game. It is co-inhabited by two separate species of life: humans, and the Locust Horde, a collection of various species from Sera's underground.

Overview
The planet of Sera was once much like Earth. It had oceans, mountain chains, and numerous cities. Most of these landscapes were destroyed by the scorched earth tactic the C.O.G. used in an attempt to destroy the Locust, now, 90% of Sera has been transformed into a bombed out wasteland occupied by The Stranded or Locust soldiers. The only place that is even remotely intact is the Jacinto Plateau, the last vestige of the human survivors on the planet. Sera is also home to the Hollow, a gigantic network of tunnels the Locust used to attack the human cities above. The state of these tunnels is currently unknown, as the detonation of the Lightmass Bomb (Supposedly) completely eradicated most of the tunnel network. However, the exact size and length of the Locust caverns deep underground is unknown, leaving the possibility that not every locust cavern was destroyed.

History
Most of the history of Sera before the events of Gears of War is unknown. But the book Destroyed Beauty, that comes coupled with the game's special edition, tells us about some events of Sera's past. Sera was once a peaceful planet. The humans of Sera had overcome their differences and lived together in harmony, and the planet had entered a golden age of peace. However, the search for constant fuel sources led to the discovery of Imulsion, a substance found just underneath the crust of Sera. Imulsion was relatively worthless, until a technique called the Light mass Process was developed, this process enabled Imulsion to be made directly into energy. Giant cities were built on top of Imulsion hot spots, which became targets for various nations on the planet. Soon, attacks were launched by nations that didn't possess the new fuel source. These attacks led to the Pendulum Wars.

The Pendulum Wars lasted for 79 years, until Emergence Day. On this day, a race called the Locust attacked and destroyed a quarter of Sera's population, following this, survivors headed for the Jacinto Plateau and the Coalition of Ordered Governments (C.O.G.), became the new leaders of the surviving population. A massive counterstrike ensued, destroying most of the planet in one fell swoop. The C.O.G. also organized an army to fight the Locust, which leads to the events of Gears of War.