Grave Eclipse

The Grave Eclipse is a phenomenon that plays a central role in. It is brought about by the activation of Eclipse Tower.

Background
The Grave Eclipse is a phenomenon brought about by the Eclipse Tower located in present-day Belinsk. It takes the appearance of a normal solar eclipse, though the effects are anything but normal. Through this process, Eclipse Tower has the ability to absorb the light of Sol; this causes the tower to emit a dark aura that envelops any region under the shadow of the eclipse. The dark aura emitted as a result of the eclipse has the effect of unleashing thousands of vicious monsters to appear and slaughter anyone who approaches them.

Eclipse Tower can only be activated when a Magma Orb is used to power the Alchemy Dynamo hidden deep within the Belinsk Ruins. The Alchemy Dynamo then unseals Eclipse Tower. It is implied that the Grave Eclipse will end when Eclipse Tower has absorbed a predetermined amount of light, at which time the light would be released in a cataclysmic burst.

Story
The first Grave Eclipse, brought about in ancient times, was triggered accidentally, by ancient Adepts known as Jenei. The Jenei's goal was to control the fundamentals of light and darkness, but Eclipse Tower was too effective in this task. At some point the Eclipse ended, and the Alchemy Dynamo and Eclipse Tower were sealed away in an attempt to prevent another occurrence. Additionally, the Jenei created and hid items that would assist future generations in accessing the Apollo Lens, a machine designed to prematurely end a Grave Eclipse. These machines would lay dormant for a unknown but lengthy period of time.

Thirty years after the Golden Sun event, Matthew and his friends are manipulated by the duo of Blados and Chalis into completing objectives that will allow the Eclipse to occur. Eventually, they are tricked into retrieving a Magma Orb from within the Mountain Roc, stating that the Sanan royal Hou Ju would die at the hands of the Morgal beastmen if they did not. Though the Adepts are reluctant to obey, Hou Ju's brother Ryu Kou steals the Magma Orb and travels to the Belinsk Ruins with the goal of saving his sister. The Adepts follow and the ruins eventually force the Adepts to the Alchemy Dynamo. At the Alchemy Dynamo, Blados and Chalis arrive with Arcanus to distract Matthew and co. while Arcanus manipulates Ryu Kou into placing the orb onto the pedestal, thereby triggering the Grave Eclipse.

Almost every city under the Eclipse's shadow suffers some sort of devastation as a result of the Eclipse-empowered monsters. Some cities, such as Belinsk and Kaocho, are shown to have high death tolls. However, three cities in the affected region, Harapa, Passaj, and Ayuthay, are able to come through the Eclipse mostly unscathed. Passaj's Alchemy Forge creates a fortress around the city that prevents monsters from coming in, while the people of Ayuthay hide in the underground portion of their city. The people of Harapa are saved thanks to the water-driven lights of their town, as well as the town's tough walls.

During their travels to end the Eclipse, the Adepts that Eclipse Tower can be prematurely deactivated only by use of the Apollo Lens, a machine located at the Apollo Sanctum. The lens can only be activated by use of three orbs: the Blue Orb, Red Orb, and Yellow Orb. In addition, the Adepts must find the Umbra Gear, a set of gear designed to protect people from the intense light of Apollo Sanctum. Matthew and co. eventually make their way to the sanctum, place all three orbs in their pedestals, and reactivate the lens. After the final battle, they use the lens to deactivate Eclipse Tower, thus putting an end to the eclipse.

Arcanus seems to want the Apollo Lens reactivated and used to end the eclipse, despite having a hand in starting it, though the reason why is unclear. Also after the final battle, when Matthew attempts to climb up to the lens, he warns him not to keep trying, and after a couple lines, nothing is heard from him for the rest of the game.

Enemies
While the Grave Eclipse is occurring, certain enemies can appear within the confines of it's radius.

Trivia

 * Battles set within the Grave Eclipse use different music than normal battles.