The Timid NPC's Secret Boss

Lila Jahn is the most timid low-level Non-Player Character in a horror game. She is afraid of ghosts and players, yet she delivers milk every day to Jasper Peirce, who appears frail and sickly. She has no idea that the sickly man she has been trying so hard to protect is the SSS-rank final boss feared by all players. Until she is accidentally teleported into other horror Instances, strange rules begin to spiral out of control, and every other boss goes out of their way to avoid Jasper Peirce. Lila Jahn finally realizes that the sick patient she has been taking care of is even scarier than ghosts.