A new promo for next week's episode of Legion reveals the identity of the show's "Yellow-Eyed King," and it's exactly the classic X-Men villain many fans predicted.
Spoilers ahead for Legion.
According to the preview, the "Yellow-Eyed King" is none other than Amahl Farouk, the Shadow King. What's more, the promo implies that Lenny is the Shadow King.
This adds up, due to Lenny's conversation with David that his father did not want them to meet. In comic books, David's father (who has still gone unnamed on the show) is Professor X, who has a decades old rivalry with the Shadow King, a powerful psychic entity. In fact, it was Shadow King who paralyzed Professor X and led him to found the X-Men. The Shadow King also has the ability to take control of host bodies, so he could easily be hiding right under David's nose.
So far, the clip has not been released online, but a third party has uploaded a lo-res version:
Legion: Chapter 7 airs March 22 on FX.