Post Onyx Storm Villain Discussion

I've read Onyx Storm and I am currently debating, who will be the "hidden, high ranking venin" mentioned by Jack.

It could be General Aetos. He's clearly an unpleasant antagonist for Violet, and he does have that pesky link to Panchek. Aetos being venin would serve us as a foil for Violet's mother, who appeared a villain but cared for her children, contrasted with Aetos, who was supposed to be a good guy, but renounced his own son. It would also cement Violet & Co's faith in Dain, once he discovers his father to be venin and helps take him down, maybe protecting someone's sister, maybe helping said sister avenge an important loss.

It could be Melgren. Lots of power, zero morality, a lot of information to wield, a power that I can easily see be a temptation to augment. Varrish could have been an apprentice, and as soon as Violet dispatched him, Melgren's Sage got themselves a new apprentice.

Aaric developing a better version of Melgren's power could also mean that a) nature is looking for balance, b) Melgren sees just regular battles because he stunted his power early-ish on by becoming venin c) he foresaw Violet and co being defeated and yet, he wasn't right.

I could of course be missing someone.

Do you agree? Absolutely disagree? Have a better theory?