Note from Pialat's wiki page:
His birthday, August 31, is the same as Megan MacGregor's... a date that had also cropped up earlier today.
- Maurice Pialat (31 August 1925 – 11 January 2003)
Okay... and staying on the MacGregor theme, they happen to know a "Seth" (close enough to "Sett"), and have written about him many times. Here's the link to one of the posts from the MacGregor's blog:
Set, who is all about discord:
Set or Seth ... is a god of the desert, storms, disorder, violence, and foreigners in ancient Egyptian religion.