Blood Spirits are the remnants of the past owners of bloodlines, e.g. a
regent my commit bloodtheft upon another regent thereby gaining part of
his/her bloodline. Blood spirits haunt a bloodline but usually only in
cases where the bloodspirit was murdered etc. This makes an excellent
starting point for any adventure where the haunted regent must somehow
appease the bloodspirit, or lay it to rest.

I think this is an idea that can be developed a lot further . . . any comments??

I believe it already has been developed-Hamlet and MacBeth