Shadrack

Very little is known about Shadrack other than that he is a powerful wizard. He is the author of the note found in KQVI, but does not appear in any of the games himself. Shadrack may be the head of The Black Cloak Society, or he may only be a high-ranking member.

In the Companion's novelization of KQ6, and within the game, there are 2 notes one written to Shadrack, and one written by Shadrack. According to those notes his nickname is "Shade".

Shadrack in the Unofficial Games
Shadrack appears in The Silver Lining, but it is unknown how big of a role he will play.

He was to appear in King’s Quest IX: It Takes Two to Tangle as well, as the major villain.

Real Life
Shadrack was a character created by Jane Jensen. However Roberta Williams had no part in his creation, or the creation of the Black Cloak Society, nor does she remember much about those details. Its highly possible that he would have never shown up in any official King's Quest games after KQ6, as long as Jane Jensen wasn't on board.

"The 'Black Cloak Society' was never an actual term that I instigated or thought up. I'm not actually sure where that came from. The closest thought that I have on that subject is that: when I was working with Jane Jensen on King's Quest 6, and we thought up the evil vizier, we talked loosely about the possibility of putting Mannanan, Mordack, and the vizier together as group -- possibly -- in a future King's Quest. There was loose reference to the possibility in King's Quest 6, although nothing was set in stone at that time. I think that it's possible that Jane Jensen might have mentioned the possibility (perhaps) in subsequent interviews on the subject, although, I'm not sure about that. Later on, I heard about the Black Cloak Society and kind of wondered where that phrase came from, but, I never refuted it as I thought it was kind of cool and, probably, would have gone on with the idea in future King's Quests had I had the chance. And, one final thing: Hagatha was never part in any discussion of a Black Cloak Society." - Roberta Williams at SierraGamers (6-9-2003)

Real World
If The Silver Lining' makes him the leader of the Society of the Black Cloak, then Shadrack and the Father of KQ2 (AGDI) are indeed one and the same, as the father is the leader of the Society, at least in KQ2 (AGDI) Timeline.

The Silver Lining team has said they are only following the original King's Quest continuity, and not KQ2 (AGDI), and because of that they will not be using the "Father". So even if Shadrack turned out to be the leader of the Black Cloaks, he wouldn't be the Father in the The Silver Lining storyline.