When we first meet Bess, she mentions that she has some sort of grudge against Jehenna. I don’t think it has come up again but I could be wrong. Either way, what did Jehenna do to piss off an incognito goddess.
Well, we haven’t heard yet what exactly occurred, but I’m sure it has to do with Lenamare and Exadore’s fight for The Book. I’m sure Jehenna did something during a confrontation.
Or maybe Jehenna enslaved one of Bess’s followers? The Nigur(whatever, can’t remember the spelling) may have sent some souls in undercover, and Jehenna enslaved one, or killed one. Really no way to know unless it comes up later.