My Classical Japanese dictionary contains no entries for "so[w]o" written as above, nor anything for "kishi" (assuming a top-bottom-right-left sequence). Even reading clockwise, so-ki-wo-shi or ki-wo-shi-so makes no sense.
The character for "shi" in the sense of death also is entirely different to the one shown here, so I don't think that's a likely lead (Japanese abounds with homophones borrowed from Chinese, which is exacerbated by the relative absence of tones).
As you noted in a different context recently, we need to proceed on facts rather than suppositions, and the meanings of the individual characters are as I stated in my initial reply.