Metatron is the Murder Hornet
Hear me out. The Metatron is a bitch no matter what. Way back before the bookshop burned, he was a manipulative twat to Aziraphale, but we only ever saw him as a Wizard of Oz style giant floating head. So when we meet The Metatron's corporation is S2 E6, we assume that this is the man behind the curtain, yes? This is the "heavenly" authority who stands between God and the rest of the angels. Are you with me so far? So tell me, why is he wearing Hell's color palette? Black topcoat over a black (or at least very dark gray) sport jacket. Even his shirt has black stripes. His tie is black with his signature sapphire blue sigil design. You know why? Because The Metatron is a demon. Now that I've probably pissed off about half of the fandom, let's dive in.
I'm going to accept that the corporeal form of The Metatron that we meet in S2 E6 is the man behind the curtain. But I'm wondering if, in the same way that the Wizard of Oz floating head spectacle is just a projection the actual wizard (a two-penny magician from Kansas), the Floating Head Monstrosity (FHM) is a projection The Metatron has rigged up rather than The Metatron himself. Essentially, the FHM is the projected "essence" of the asshat with whom Aziraphale spoke before the bookshop fire, the same one who wanted to discipline Gabriel and strip him of his memories. And if it is merely a projection, like the Wizard of Oz floating head, the man behind the curtain is likely in a different physical space.
If The Metatron can control the FHM remotely that suggests that he (the corporeal form or spiritual essence of the Metatron) isn't necessarily stationed in Heaven. Perhaps he can't even get into Heaven, but has managed to project his presence there to manipulate the Heavenly Host throughout the course of history.
Sidestep along with me while I take a quick detour. I promise it's relevant and necessary to understand the implications of The Metatron's arrival in Soho. (But I'm a demon. I might be lying.) Good Omens relies heavily on mirroring* as a narrative technique. One of the most obvious places we see this structure is in character sets: Crowley and Aziraphale, Newt and Anathema, Shadwell and Tracy, Nina and Maggie, Gabriel and Beelzebub. The character sets function as mirrors of one another (angel and demon, witch and witchfinder), while simultaneously reflecting other character sets in the story (Nina and Maggie reflect Crowley and Aziraphale, etc.) But we also see it repeatedly through plot structure--the pair of 1941 flashbacks in S1 and S2; the way S2 begins with Azirphale moving toward Crowley and ends with him pulling away. My personal favorite reflected imagery in the whole damn show is when Aziraphale shields Crowley from the first rain in Eden and Crowley shields Aziraphale from the celestial hailstorm Before the Beginning.
Alright, let's re-route back to Soho, to The Metatron's introduction in S2 E6 and how it embodies mirrored structure. The first shot we get of The Metatron in Soho in S2 E6 is when he's buying a cup of coffee from Nina. He's not actually identified as The Metatron in this scene, and Nina just views him as a regular customer. Next, we see him enter the bookshop and approach the Archangels, none of whom seem to know who he is. In fact Michael just assumes he's a human, tries to shoo him away, and even asks him, "And who are you?" The Metatron never gives his name; instead he presses the angels, "You don't know me?" He then addresses Crowley, "What about you, demon? Do you know me?" It's at this juncture that Crowley identifies him as the big giant floating head, and Aziraphale, in a rush of comprehension shouts, "Oh, The Metatron!"
This scene's other half is the introduction of Bildad the Shuhite in the Job flashback sequence. Crowley presents himself to Job and Sitis, who do not recognize him. When questioned about who he is, he says to Sitis, "You tell me." Sitis proceeds to identify as him Bildad the Shuhite. Crowley shrugs and agrees to the suggestion. This mirroring of dialog shows us that in both scenarios, there's deception in the presented identity. Just as we can't trust that Bildad the Shuhite is who is says he is, we similarly can't trust The Metatron's identity at face value.
When it comes right down to it, The Metatron is a pretty sketchy character. During his S1 interaction with Aziraphale, our angel doesn't even know who he is. The Metatron has to introduce himself as the Voice of God, a go-between, if you will, whom Aziraphale, in all his ageless time in the universe, has never even met or heard of. Dodgy? You betcha. When we see him in the Gabriel trial sequence during S2, he's just one of the several floating heads overseeing the progress of Armageddon Round Two. We're able to gloss over the fact that he's presented as a floating head fairy, because all the angels appear as floating heads in this sequence. However, unlike Uriel, Michael, Saraquel, and Gabriel, we never see The Metatron interact with the other angels in anything resembling a corporeal form.
So with this evidence, let's return to mirroring structure as a narrative device: a Clue to point us to the crux of the deception that The Metatron is performing. But to get there, we'll need to look at the reflected plot beat for context.
At the end of S2 E5, Crowley needs to get into Heaven to access information about Gabriel. Problem is, since he's a demon, he can't just waltz into the Heaven-Hell-evator and go to the up. He needs an angel to escort him, so he tricks our beloved Inspector Constable Muriel into arresting him: "I'm a demon with knowledge of a crime against Heaven. I demand that you arrest me!" Crowley uses the art of deception to sneak his way into the Heavenly hive.
Once in Heaven, when Muriel starts to fret that she's been tricked and will get in trouble for bringing a demon into Heaven, Crowley tells her, "Angels are like bees, fiercely protective of their hive if you're trying to get inside. Once you're in....I mean....is it even faintly possible that an unauthorized demon might be just wandering around in Heaven unescorted? Bees." Muriel then worries over Crowley's outfit, telling him he looks like a murder hornet, so Crowley changes into his most wonderful and excellent angel disguise.
Still with me? Have a gold star to match Crowley's nail polish.
Crowley's gambit to get into Heaven is a clever tactic, no doubt, and necessary for the final beats of the narrative. But I believe it's also there as the first half of a mirrored plot point that we will see play out in S3. Ya see, Crowley's not a murder hornet. He doesn't infiltrate Heaven to plunder their proverbial food stores or to destroy the hive. He does his quick bit of reconnaissance and is on his way. I think Crowley's ploy ultimately functions as foreshadowing for the real murder hornet: The Metatron.
To get his full essence into Heaven, his spiritual body and not just his projection, The Metatron needs an angelic escort. That's why he's so insistent that Aziraphale joins him on his journey up to Heaven. He needs an angel--one he perceives as an easy target--to break him into the hive. And Aziraphale fits the bill. He's vulnerable, having been implicated in the business with Gabriel, which could earn both him and Crowley extreme sanctions, being struck from the Book of Life. So The Metatron coaxes and manipulates Aziraphale to accompany him to Heaven, implicitly reflecting the way in which Crowley manipulated Muriel into arresting him and accompanying him as his Heavenly escort.
Do I still believe that The Metatron manipulates Aziraphale in order to divide the angel and the demon who, when working together, can produce miracles of un-paralleled power. Oh, hell yes! But that's not something only Heaven would want to mitigate. The sheer miracle force Crowley and Aziraphale manifest when working together is a threat to any oppressive structure that wants to consolidate power, and that certainly includes Hell. The fact that The Metatron realizes he can separate the angel and the demon in the same stroke as infiltrating Heaven is icing on the cake.
So there ya go. That's all I've got for today. Is The Metatron a Demon? Honestly, I don't know. But it's too interesting a theory for me to leave it alone.
*Please note, I'm intentionally using the term mirroring rather than chiastic structure to make this analysis. I deliberated for a while, but decided that it'd be a little loosey-goosey in this situation. So, yes, I am aware of chiastic structure and it's use in Good Omens, I just don't think this quite matches up.**