#SHE READS THEORY...SHE TALKS TO ME ABOUT CURRENT EVENTS...but ONLY for india...it's SO weird

[meteorherd]

still absolutely BAFFLES me how my mother will completely seriously say "yeah india's government is built on fascism and nationalism and the only way to do anything substantial about it is through a communist revolution" and then turn around and be THE most painfully centrist person ever about american politics

[thessaliah]

Who is the “Person of Chaldea”?

For those who didn't know, there is a mysterious helper who appears in the Lostbelts and aids Chaldea indirectly by helping the people they made contact or would make contact.  Here cut under spoilers the information we have and already old destroyed guesses and theories:

We know little about this man (assuming is a man which seems most likely right now) who appears in Lostbelts when Chaldea isn't around to give a helping hand. The direct (not speculation related) info we have is:

He is referred specifically as the "カルデアの者."

Wears white.

His clothes are dirty and tattered, covers his head and face with a hood.

He apparently fights with a curved, thin sword or something alike it (note this is an old Yaga describing this so if he was using some magic trick he wouldn't know).

He knows magecraft of the Ages of Gods that isn’t rune based.

He knows how to treat injuries, plague, and has the skill as a physician. He is called a 'sensei' in LB3.

Knows assorted skills like how to take care of fields.

He is able to manifest in the Lostbelts by mysterious means.

Pronouns: 私 and お前 to address others.

He has a 'tch' tongue clunking quirk but he claims is because of his sore throat and body.

He is shocked to find people who would put themselves in a disadvantage to offer him kindness and hospitality.

He seems detached about humanity at some level and a pragmatic point of view.

He might appear different than he used to look or have a different body.

He says his goals haven't changed and he has done the same things in the past (without such welcome). "His actions are the same."

Holmes speculates he’s a “survivor of Chaldea.”

Those are the official things we know. There is more I could add that could be related to him but that goes in identity theory.

DEBUNKED: MUSASHI+ DIFFERENT SERVANT ON EACH LOSTBELT

When Musashi appeared in LB1, plenty of fans (and even the characters) assumed Musashi who also claimed as an ally of Chaldea (but using a completely different label and not カルデアの者) was this mysterious helper: she had covered her face with a hat, she wielded a katana and all. But they didn't notice the lack of quirk and the lack of healing expertise. In LB2, the Person of Chaldea is an overpowerful mage, so ruled her out unless he was a new one. By LB4, it leaves clear that is the same person that travels in all Lostbelts, he gets dialogue and internal monologue for the first time. Leaving the theories of Musashi, Ryoma, Muramasa, Paracelsus, etc out of the running.

DEBUNKED: IT’S A CRYPTER

Before LB4, there was a popular theory the Person of Chaldea was actually a Crypter, in particular,  Kirschtaria Wodime, because he favors white. But after LB4, we know the man travels alone and that for a Crypter to move between Lostbelts, they need the help of an Emissaries. Evil Mercenary Tamamo is good for such task. Crypters are more than antagonists but they are unlikely to be the Person of Chaldea.

POSSIBILITY # 1: IT’S A NEW SURPRISING CHARACTER OR SOMEONE UNEXPECTED LIKE MARISBURY ANIMUSPHERE

Because the person is hard to fit on the old characters we know, perhaps it's a new one. Abe no Seimei is a good possibility when there are characters related to him introduced. Murasaki, his student, his foes Tamamo and Douman. However, my only complaint here is that they yanked our chains for two years of mystery to introduce a new character? The possibility exists, but it seems like poor writing. If we are talking of dark horses, Marisbury Animusphere is certainly another possibility, although the pronouns don't fit, and he has no notable physician experience that we know, he wears white, he's from Chaldea, and the shoes (not the coat) match the man in the OP. I mean to put him here as a possibility he's connected, but my suspicion is that Marisbury is more unfortunately linked to the antagonist, the God of Another Planet. I'll leave that for another post. His possibilities to be the Person of Chaldea raises if Daybit is an antagonist and not the potential aloof ally he seems to be.

POSSIBILITY # 2: IT’S SOLOMON

Romani, Goetia, a combination, etc. Solomon. "But Solomon disappeared!" I can cite a lot of things, from Goetia voicing the PV, to Roman in the Lost Room, to the fact both left remnants (which Ars Nova shouldn't have allowed) and Chaldea is stated to want to build a record for Romani specifically. But I frankly don't care about this, Nasu would explain this if the time comes. The Lostbelts have revised the Modern History anyway, and whatever happens inside their Wall of Storms is not "our World" technically.

So far is the most likely possibility, and why there's a tease and red herring from one or the other. Unrelated but completely important is the scene in the Lost Room, the final shot of someone picking up one of Solomon's rings from the thrones before leaving. The question remains is which Solomon?

THE CASE FOR AND AGAINST GOETIA: "Goetia is in Romani's body" seems to be the most popular theory since the OP image show up (along with the initial "was that Marisbury?"). Goetia does use, among other pronouns, watashi and omae. The personality of the Person of Chaldea seems colder and harsher than Romani usually displayed, so fits more Goetia, as well as the fact of "is this appearance?" which makes him mull over how he's treated, which could refer to wear Romani's body and clothes as he did to Solomon. Maybe he gained medical knowledge too. However, are we sure is him or Nasu wants us to assume is him for taking to face some superficial statements? The main case against is that his current actions don't match his past ones, even if one is to assume his goal and motivation remains the same (he feels sorry for humans), that he has indeed wear Roman's likeness in the past (with Mashu) and he shouldn't be shocked about the benefit of a human appearance when his shtick was passing himself as Solomon or Roman or making his pillars take human vessels. The other case against is the tsking. Tsking and tongue clunking to my memory are not one of his quirks. IMO, Goetia is a strong if not the strongest contender. I'm not sold about Roman's body, because Roman's body disappeared (and I feel it's irritating for his sake and Roman he's still under his shadow rather than stand as his own character), the tongue quirk could be because whoever body he’s using or inhabiting has it. 

THE CASE FOR AND AGAINST ROMANI (SOLOMON): "A doctor in white" was the second most popular theory but fell off a little after the monologue of the Person of Chaldea because he lacked Romani's nicer personality and his usual pronouns (Boku/kimi). It's true it cannot be the same Romani Archaman we know, but this doesn't mean it cannot be him. We'll start for the case for: a physician with assorted talents (all that could be feasible for Romani/Solomon - and yes, includes having a legendary long thin blade listed in wikipedia - and this also can be listed on Goetia’s favor too!) that wears white, is from Chaldea, and still has the same actions, goals, and motives. The actions might have been weird, but with episode 0, we saw Romani walk the world on his own and doing odd jobs including acting as doctor in disaster zones, until he turned to Chaldea to complete his mission. How is that different from the Person of Chaldea’s present actions? The main objections are sound: the man doesn't talk or acts (in temperament) like Roman, and the quirk isn't his. However, after becoming Solomon again did use watashi and omae (he switched gradually from boku to watashi in the temple, if you carefully replay his unused voice clips and read his farewell scene) and his personality would be different if he was in possession or manifestation of a new body, as most Pseudo Servants (Ishtar wouldn't act like Rin if she wasn't in Rin's body, for example, we know this from Strange Fake - the vessel influences the spirit). The Servants who cannot manifest alone require vessels and the vessels can influence the way they talk, their temperaments and -obviously- give them a new appearance which our Person of Chaldea might have. Despite his friendliness, Romani seemed to speak and think of humanity from the distance (Accel Zero comes to mind where he reveals he's pretty  pragmatic who wouldn't go around to change things as Waver did), he also thinks people should hate him (in his Blurb of relationship with the Master), so if it's Solomon post Roman's self-loathing, him acting surprised that those people in India Lostlet are willing to accommodate him with the little they had and were so kind toward him is unfortunately not as weird as we might think. Da Vinci changed from a sassy libertine to a (dull) angelic younger sister type after her rebirth just after the Prologue if we need a precedent. 

As for me, whoever the person of Chaldea is, I would prefer if Roman remains Roman. I absolutely dislike the change in Da Vinci (looks and personality) but I am not blind not to see the possibility with the metaphor of the "peppermint green book" in the latest event the doctor appeared (you know that whole “things -people-  you believe lost might be returned to you but with differences”). There is another case I'm considering but is more self-indulging, because doesn't mean desecrating Solomon's second corpse (even if it disappeared!), Goetia's arc, and Romani's whole self. The one of assimilation like Kingu and Enkidu which means the Person of Chaldea could be a new Solomon created of Romani and Goetia mutual elements. They used to share a body. That’s another case, but I’m not sure. My heart leans closer to Goetia in this, but my gut feels he could be red herring for Solomon 2.0.

Of course, this could be all be wrong and it’s truly Abe no Seimei or something outlandish like Future Ritsuka (I forgot to debunk this, it feels laughable when Ritsuka has a very limited character or arc, and cannot do a single healing spell to know magecraft of the Ages of Gods - plus would give Gudako an edge over the male Ritsuka -who uses ore as pronoun- and that won’t be allowed, sadly). You never know. I just wanted to share past and present theories. From a writing perspective, I just don’t think some new character would be right when they are treating this as a slowburn mystery arc and purposefully used Musashi as an in-game red herring. Maybe if Abe no Seimei -or whoever if it’s a new character- gets a better set up, certainly. Marisbury possibility is still strong if he’s not an antagonist.