Board Thread:General Discussion/@comment-7342272-20171108034153/@comment-2602:301:77AD:9270:F84F:32DD:5F3:2DD0-20171108222817

So even though 系譜者 isn't a word, it seems to me, based on the context it's being used in and what information on 系譜 I'm getting, I believe that it means "someone who has lineage", the lineage in this instance being a connection to gods. So "heir" seems like a decent translation, or maybe "inheritor", to make it sound more lofty.