I also thought about G'Henna as an allegory about the Ucranian Holodomor and the hunger for Mao's great forward step, but I am afraid in this case they were too subtiled. I notice I can't "cancel" the trope of "evil preacher", like the character Harry Power from "the Night of the Hunter", the reverend from "Brimstone"(2016), Leland Drury from Disney's "White Fang 2: Myth of the White Wolf", Caleb (Buffy the vampire slayer) or the ghost reverend Henry Kane from Postergeist (2 and 3)...but I can warn we should avoid the possible abuse of certain tropes.
* We have to remember the metagame reasons because lord Sorth escaped Sithicus. I imagine two Sithicus, one of them is in the shadowfell of the Krynnsphere, and the second is the dread domain in the demiplane of horror. There are some portals between both, but the travel doesn't worth it. The "Krynnverse" Sithicus is "ruled" by four dark lords, Raitslin (punished before he was about to become a god), Ishtar kingh-priest, lord Sorth and Kitiara, whose soul within a magic gem.
* The dark powers' goal is not the punishment or torture, but there is other reason, like a test, for example. They dark lords could have been killed, destroyed, and their souls sent to the infernal planes, but they still have got some opportunity to the redemption and the end of the curse. Maybe a theory is the dark powers are psychologically torturing the dark lords to force these to do something, maybe the escape of the dark powers in the material plane.