Pendulum Wars and E-DayEdit
During the Pendulum Wars, a series of bomb shelters were built in the town. During the wars, the UIR attacked the town and shattered it. Sometime after this, E-Day would follow and the city was evacuated. However, it was largely unaffected by this initial attack, and Maria Santiago's parents were buried there after E-Day. When the Hammer of Dawn counterattack began, the town was spared from the strikes, but it had a grandstand view of its neighbor city Char as it was flattened.
- "STAY OUT!
NOT SAFE FOR HUMANS!! any actual people (not un-people) coming to Mercy should STAY AWAY because there is something really weird going on like some kind of CRAY FEVER or SOME OTHER CRAP and I'm likely to SHOOT YOU if I can't tell you apart from those sickass freaks!
They're not gonna stop unless I stop them!!!!"
- — A warning letter about the pandemic posted in Mercy.
Two years after the sinking of Jacinto, the town of Mercy became a major area of activity for refugees who came to rely on its primary Imulsion pumping station for resupply. However, in 17 A.E. its Stranded population faced an epidemic that was worse than Rust Lung. Serans in the town began falling ill with symptoms including fever and muscle pains. As the epidemic began to spread, the citizens of Mercy tried to fight it by boarding up the homes of the ill to keep it isolated, but it failed. In just a few short months, most of the town was affected, except for a few survivors, including one crazy old man who rigged the pipeline running through the town with explosive charges. He believed it was the Imulsion causing the epidemic, and wanted to keep it from spreading.
Delta Squad arrived in search of fuel for their trip to Azura, but found the town deserted and the fuel pump shut off. They followed the pipeline to find the fuel pump, and discovered the charges placed on the line. After deactivating the third charge, the crazy old man shot at Delta Squad and warned them about the 'fever' before running away. They soon discovered that the crazy old man had died, not by Locust but by a Former, a human who has turned Lambent. Swarms of them packed the area, and Delta Squad was surrounded, but they pushed their way towards the town hall, only to find themselves blocked. Swarms of Formers begin to attack them, and a Stranded on the balcony above them informs Delta to get on the machine gun to fend off the Formers. After defeating the wave of Formers, Delta Squad joins the Stranded inside, but before they can ask anything more than how the Lambency starts, more Formers ambushed everyone inside. The Stranded are immediately killed, and Delta Squad pushed through the Formers to the church, where they discovered the fuel pump. As the rest of Delta activated the pipeline, Dom visited his family's grave and left his COG tag along with Maria's necklace there. The pipeline was successfully activated, but the tanker was too heavily damaged to hold the Imulsion, forcing Delta to abandon their plan. They got back to Dizzy and Jace but were ambushed by the Savage Locust, and then the Lambent came to join the fight. Delta fought them off until Dom sacrificed himself by driving a truck into the tanker, detonating the Imulsion and destroying the enemy forces.
The attack left much of the deserted city destroyed, and its Imulsion pumping station rendered inoperable. The remaining Lambent and Locust infesting the city and its surrounding areas soon after were wiped out by the activation of Adam Fenix's Imulsion Countermeasure Weapon.