Shikin suddenly died at the age of 26 and the Team XII of Grim Reapers are in-charge to protect her soul from Devourers and guide her to the afterlife. However, Shikin was not permitted to continue with the afterlife because surprisingly she had committed a mortal sin before she died. She was oblivious about it and beg for the Soul Judiciary to give her another chance. The Soul Judiciary sentenced her to serve as Grim Reaper under Team XII until she uncover the mortal sin she had committed.