JK Musou: Owaru Sekai no Sukuikata

Fictional creatures have overrun the world, bringing society to the brink of collapse. The protagonist discovers a unique ability within themselves. As they engage in battle, they gain experience, new skills, and the capacity to use magic. A reclusive high school girl becomes part of a group designated by the system as "players." She chooses to fight the monsters and protect those around her, while also embracing the relaxed lifestyle that the apocalyptic situation has provided.