Seoul Station's Necromancer

After being forcibly summoned to an unfamiliar planet, former high school student Kang Woojin returns to Earth after twenty years away. But the world he comes back to is no longer the place he remembers: Gwachun Station has become a prison, and he finds himself confronting a changed Earth. Woojin’s strength and age have both been reset to nothing. He must start over on the path to becoming Earth’s strongest necromancer, while holding on to the world with the power of his limited forces.