From Earthbound Spirit to Immortal

Shocking! A handsome, dashing, refined little boy was found burned to death in his rental apartment, his face flushed red. Was this a distortion of human nature, or a collapse of morality? What? He died and became an earthbound spirit, refusing to leave? What? You say you bound a System called the Underworld, and even as a ghost, you’re determined to be the strongest one around?