Spoilers follow for this episode and the comics on which Legion is based.
Things are beginning to fall into place in this fifth week of Legion — well, by Legion standards they are anyway — as we now have a better sense of Lenny’s true nature, and that of the Devil with Yellow Eyes, and of David himself.
Not that David is quite himself when “Chapter 5” begins. Having escaped the astral plane at the end of the last episode, with the not-so-nice Lenny persona now in tow, David is a little too cocky, a little too self-sure back at Summerland. While his newfound mastery of his powers allows David to create a safe place where he and Syd can (seemingly) interact in a physical sense, his interactions with Melanie make it clear that Lenny is now at least partially calling the shots.