I always felt Shadrack should appear in an official game. He is a loose end. But he should be fairly stand alone villain. Much in the way for the most part villains were stand alone in each game of the series. If there are other black cloaks in the game they should be original villains. I'd rather see black cloaks as something of its own entity.
That is to say, most villains in previous KQ games except for those already confirmed in KQ6 and possibly KQ5 (Roberta had said Manannan may possibly be a member), have nothing to do with the organization. Please.
Maybe toss in a bit of a classic mystery style story. So a kind of investigation is required. Shade doesn't necessarily have to be the leader (he probably isn't), he could just be another cultist in the ranks.
Ultimately the game ends with the destruction of the cult, or at least sets up for the hunt of the real leader in a later game.
I personally wouldn't mind Jane Jensen coming back to help with the ideas, or get it closer to the ideas as she originally envisioned. Unless her idea was for full series Legion of Doom, then I'd rather she stay away, as that's way too predictable.
I'd equally be fine (and prefer) with the ideas of stopping Shadrack in the confines of a standard KQ plot, just another wizard with a plan to take/over conquer a new land. The story could have very little information on the black cloaks except for a few cryptic references. Maybe explain a few more things but still leave the organization fairly open ended. While still avoiding the Legion of Doom cliche.
I read about the Black Cloak Society on the KQ wiki, and IMO, it appears that the Society is just a society where Evil Wizards hang out and share their evil plans with over chess - That would be an interesting take on the society -I would love to see the society handled that way in a canon game
LOL, just a mere men's club, with no nefarious plans to conquer the entire world. Just individual wizards and magicians concerned with their own lands to conquer
. Maybe they don't just play chess, a little 'dice' (Alhazred has a pair of ivory dice in his belongings), some blackjack, backgammon, checkers, othello, cribbage... etc! That would be so ironically funny
Btw, i've expanded the informationon the canonical Society of the Black Cloak, within the article on the KQ wiki. I've added more information from the games and KQ companion. The new information added a discussion of hiearchy and modes of communication, as well as the correspondence between Shadrack and Alhazred.