Originally Posted by
fumei
Max already explained how that's a faulty line of reasoning. In this LB, fairies don't have lineage per se, but they exist as "types" of fairies, basically. So a fairy will be born with the "lumberjack" role/purpose and be driven by this/live by it. They won't give birth to a new fairy or anything of the sort, but eventually (when they die, usually) a new fairy of the exact same type/with the same purpose of "lumberjack" will be born, and in that sense they form a sort of lineage.
Morgan in the LB specifically is a special kind of fairy from "paradise" (implied to be the reverse side/inner sea, I guess) with the specific purpose of "righting what is wrong" (artoria later basically says this comes down to "get rid of this britain"). However, because she abandoned this purpose more or less, "paradise" has to give birth to another fairy to take over that same purpose, just as if Morgan had died, effectively. That's what Artoria is. If anything, it's more accurate to say she's Morgan's "successor" than being Morgan herself, but even that's not entirely correct. They form a lineage of sorts, a "set" of fairies who share the same purpose, just as the fairies of a clan likely all share similar purposes and come together under it.