Corrected entry: Jen reads (as he learned to do from the Mystic who raised him) the hieroglyphic prophecy, and in doing so, gets a "mission briefing." The problem is, the Mystics understand all of this, so why didn't any of them tell Jen these things as he grew up, or if nothing else, right around when "his" Mystic died and or before he set out for Augra?
dizzyd
3rd Aug 2019
Correction: Spoilers: When the Urskeks split into the Mystics and the Skeksis, each half got certain character traits. The Mystics were peaceful and kind but had but no drive or ambition (which the Skeksis had plenty of). So it just did not occur to the Mystics to teach Jen what he needed.