I dunno but here is an idea = maybe he "killed" her so to turn her into a semi dead (kinda angel like but he seems to have the controlle of when she turns alive and into ghost) and maybe the swird the assasine used was somewhat magicall and the reason she cant find her own body is that it is inside of here like she is swaping with realy body (thats atleast my idea of it idk)
I dont know what to put here ! I saw some people making like a dating profile > i am 19 bla bla bla < but i wannt to stay mystery ya can guess my age and country hehe (ФωФ) now bye bye ヽ(￣▽￣)ノ