Oka, a 5 centuries year old spirit, war veteran in a demon war, supporting demon slayers. Now she's retired and the Spirit King has reassigned her the job to guard lost spirits who can't become reincarnated, or pass on to heaven or hell. (Some information Lost Spirits become children again) Can she make it work? Will she be able to care for the lost spirits of children who used to be demons? Can she sooth the traumas they suffered as demons? Will she be able to adapt to her new life as a guardian for these lost spirits? And will the one who caused them this pain come back for revenge on them failing him? (This is Demon slayer for y'all's information)