Caius took off rather quickly, which surprised Eden considering most people aren't used to running across rooftops. He mentioned the mural at the library, it sounded like a likely place to Eden. It held importance of the city and was at the figurative heart of the city. He hoped this mural would at the very least point them in the right direction, if not the world may be lost. Eden wasted no time in following Caius, the city wasn't extremely large, and the boy said the library was near. 

As Eden leaped from building to building he could see the horizon disappear into nothingness. It was an unnerving and scary feeling, like the darkness was pursuing them specifically, but it couldn't be. Mere heartless were not driven by motivation or thought, they were driven by pure instinct. They would devour everything in their path and consume any heart in the proximity. The thought of heartless reminded Eden that this new guy had no idea the threat they were facing, so he took it upon himself to educate his partner. "You should know what we are up against Caius." He said as they ran, he stopped when Caius almost lost his balance but he quickly regained it and the set off once more.

"These creatures attacking your home are called the Heartless. They are the embodiment of the darkness in people's hearts. They are drawn to the darkness the lies in other's hearts, they will find it and release it so it can too form a heartless. They can only be defeated by weapons of the heart, such as our keyblades." Eden noticed several heartless leap from the ground and dive at him, he quick parried the attack and spun around simultaneously banishing the shadows. He landed across the gap, seeing just a few roofs ahead the mural that Caius had mentioned. "They are also drawn to the keyblades, they fear them, but are also driven to destroy them. Most importantly you must remember that there is darkness in every heart, including our own." As Eden finished his quick lesson, they arrived at a rooftop across from the Libraries Mural.

Eden jumped down into the town square to approach the mural, but was intercepted by something that he had never seen before. A heartless of collosal power burst through the wall of a nearby building and began to charge at him and Caius. The beast was a wyvern like beast, it sport two wings and two powerful legs. Its chest was covered in thick bone ribs and its head an armored skull. The tip of its tail burned a ghostly blue flame and the same flames roared from the back of its skull. The heartless flew into the air and began to swoop around the two, launching ghostly colored fireballs at them from the distance of the sky. Eden looked to Caius, "Looks like we have a bit of an obstacle to clear first." He thrust his keyblade into the air and channeled all his magical power into one shout, "Gravity!" The sky lit up with a purple light above the square and the heartless was slammed down into the ground, damaging its wings and preventing it from continuing its flight. This would allow him and Caius to slay the beast.