Why are there so many songs about rainbows? While Dan Stevens convincingly strummed the banjo and sang a creepy rendition of a song made popular by Kermit the Frog, perhaps the question Legion should be asking is: Why do so many TV shows equate mental illness with superpowers? On the bright side, that seems increasingly unrelated to what's going on in FX's new series. Up until now, Legion operated under a closely related query: Is David Haller suffering from schizophrenia? It seemed the series' main mutant had endured a prolonged battle with the disorder, but the closer he got to Syd and Melanie, and the folks at Summerland, it slowly became clear David is afflicted by something else altogether. Since the audience has been spending time with him things have been… well, not right. But given the requirements of a weekly television series bearing the Marvel brand the implications of his particular malady were likely going to be a little more out of this world.

As 'Chapter 5' concluded, it seemed the question has finally been put to rest. David is not schizophrenic, but rather his mind is host to a powerful other consciousness he and the audience know to be The Devil With the Yellow Eyes. While visions of the entity have been around from the very beginning, questions of David's mental health kept concerns about the bloated corpse-like creature relegated to a potential projection from his troubled mind. Legion has been wandering in and out of reality and powerful projections so frequently it wasn't much of a stretch to think this was just another component of his disorder – not altogether unlike his fractured memories, visions of Lenny, or the frequent appearance of the Angriest Boy in the World. As it turns out, though, hints that Noah Hawley's series was going to introduce David to a much larger world – one caught up in a war between mutants and humans – may have just taken a dramatic turn inward. But, in an intriguing twist, that turn may have far greater repercussions than the usual humans v. mutants scuffle that so often serves as the framework for these kinds of stories.

David's strange and powerful mind has been a boon to the series in terms of its visual aesthetic and storytelling flourishes, allowing Legion to indulge its every creative whim, from a Bollywood-style dance sequence to the one-sided ramblings of a beat poet trapped in a psychic ice cube. But it has also given the series a reputation of being a touch impenetrable, or, at least in the way it seems to favor painterly whimsy over comic book-style plot and action, less accessible than some of its superhero television counterparts. As such, Legion did its storyline a great favor in 'Chapter 5' by redefining the particulars of the plot and positioning the larger story arc not as David making his way in a world that hates and fears his kind, but as David (and the others) discovering something dark and equally powerful has been hitching a ride inside his mind for quite some time; simultaneously leaning into the idea that "everything he knows is a lie" while assuaging concerns over the sometimes ill-organized nature of that formula by pointing a finger at a single culprit.

With only three episodes left to go, turning The Devil With the Yellow Eyes into what is likely the season's main villain – after he hijacked David's body and mind, using his powers to systematically wipe out an entire section of Division 3 and cut off the head of the snake by killing Brubaker – gives Legion a greater sense of focus, one that doesn't have to rely as much on its otherworldly sensibilities being grounded by David's romance with Syd. It also affords the series a chance to define for the audience what is real and what is not – at least to the degree that the show doesn't completely devolve into a tangled web of twists and turns making the narrative and its characters increasingly untrustworthy and the point of watching it increasingly nebulous.

'Chapter 5', then, is a lot like the halo device cooked up by Kerry Loudermilk once he realizes what's on David's mind. Although it has yet to be put to use, the intention of the halo is to bifurcate David and The Devil With the Yellow Eyes long enough the Summerland gang can talk to their new recruit without a devilish set of ears listening in, hijacking the entire conversation, or wiping everyone's memory. This episode helps do the same thing; it allows the characters and the audience to finally be in the know about what's going on (or at least to start to see the edges of a more distinct conflict) without worrying the whole thing will be reset the instant everything is revealed. There's a clear villain now – it's Lenny, it's King, it's The Devil With the Yellow Eyes, all rolled up into one entity that, as was previously speculated on, could well turn out to be the Shadow King. But as far as the series is concerned, the terrifying psychic goober in the tattered suit is important for more than how he (theoretically) connects to Marvel Comics.

So far, Legion has been an entertaining if not sometimes inscrutable ride. The visual flourishes and penchant for embracing the surreal, weird, and ambiguous aspects of its "mind-blowing" narrative were slightly offset by the concern it might get lost in them, potentially too caught up in the endless possibilities and wonderment of its chosen setting. By turning inward, however, the series can have its cake and eat it too. Setting up a potential confrontation between host and parasite inside the show's favorite hangout spot (i.e., David's mind) while promising answers to questions about its character's origins affords the show an opportunity to maintain what made it interesting in the first place, and to capitalize on its X-Men credentials. As exhilarating as it may have been to see a Summerland vs. Division 3 showdown, the battle for control of David's mind is more in this show's wheelhouse, which means adding a necessary detail, like a clear villain, may prove to be the smartest thing this show's done. Rather than tease an endlessly spiraling storyline rooted entirely in an unreliable narrator's experience, Legion suggests the show is far more specific, and the answers, like the Devil (With the Yellow Eyes), are in indeed in the details.

Next: Legion: Chapter 4 – Who Or What Is Lenny?

Legion continues next Wednesday with 'Chapter 6' @10pm on FX.

Photos: FX