The males in the ruling family of Aveh (Fatimas) have always wed the Great Mother of Nisan. This results in a long line of inbreeding (if I remember correctly, Margie and Bart were cousins, but also betrothed).

Incest in royal families is nothing new, certainly. To keep the blood "pure" one had to choose from a limited gene pool. However, in Xenogears, it seems it has more to do with religion or tradition than with keeping a pure genetic line. The Fatima Jewel (blue eyes) seems to be a dominant trait, as Sigurd inherited it even though his mother was not one of the Great Mothers.

I'm totally rambling!*laughs*

Ok, so why do you think there was this big thing about the King of Aveh marrying the Great Mother of Nisan? Politics? Religion? Tradition? Just a groove thing for the relatives?

Do you think Shakkahn was planning to marry Margie after he used her for the "jewel" in order to assert his legitimacy as King of Aveh? Or was he only after the power and not politically savvy enough to think of that kind of a move?

Am I spending too much time thinking about a video game? Haha.