Embers_of_me

Pandora was once a human girl. She lived in ancient Greece, happily living life. She was a kind person.

But things had changed when the Gods rewarded her kindness with a box they strictly ordered her not to open. She, in the end, grew too curious and opened it up. Out came an evil power that overtook her and changed her kind ways.

She attacked her entire town and became a deity. During her reign as a deity, many people tried their hardest to exorcise her. All she was doing was causing chaos, as she now found great pleasure in doing.

One day, a group of exorcists found something to defeat Pandora; a gem to seal her inside of. It was successful, but a hard mission. After that, she was handed down from human to human until she reached a mad scientist.

With the mad scientist, she was grinded down and closely inspected. The scientist and their colleagues had used her to come further in their search for immortality. Some of the powdered gem parts were put into a poison. The APTX 4869.

The APTX went on to poison and shrink Kudo Shinichi, while Pandora was stolen away to a museum exhibition.

In the present, Edogawa Conan visits a museum with the Detective Boys. During the visit, he's mysteriously called upon by some unknown power. It was Pandora, who had sensed a part of herself.

Because the two both had Pandora's powers inside them (albeit too little in Conan to affect him), Pandora could grasp those powers and launch herself into his body.

Now inside Conan, Pandora roams and causes carnage like once before, with red gleaming eyes full of pride.

Deep inside the body, Conan is trapped inside. He can only helplessly spectate the body's POV, browse through memories, or create things from his imagination. Pandora cannot do this.

Conan can also see Pandora's memories. He knows of her secrets and weaknesses. From this, he haunts her dreams and makes them nightmares by using his newly learned knowledge.