Save Me if I Become My Demons

Saeran Choi, a disgruntled and restless hacker, had learned of his prison within the game world of a phone app--called Mystic Messenger. He recruits some outside help from a woman he establishes contact with, who just downloaded the app.

This woman, Marianne, impresses him as she agrees to be his "tester" of the game he pretends to be a progammer and developer of. She shares her initial strategy that in his eyes makes her ideal to have an integral role in his agenda to escape to the outside world.

(Combining my two favorite character routes, Seven's and Saeran's/Ray's, in addition to a lot of my own ideas. AU Fanfiction.)