"Hooking your players" ha! this is such a pleasing use of old etching art, so on-theme. It is a fun read, too.
I really love the horribly medieval world Stolas' terrestrial existence implies - sometimes there's just a huge flightless owl out in the farm's hinterlands. It'll eat the help! That's Devils for you!
My favorite bit of DM advice you present:
You may choose to write out twenty six weaknesses and let your players use their skills and abilities to find them, or you may simply say yes to whatever weird things your players suggest as weaknesses. There are no shortage of copies to explode. Have fun with it.
How mischievous! You do a lot with a little here, and I really appreciate the map-sigil-goetic-spirit mix you've enacted.