Like most of us, I thought there were two souls in Mu Deok's body, but after the last episode, I am more and more inclined to think that there has never been a soul other than its own soul in Mu Deok. First: in the first episode, Mu Deok has a dream before waking up in the boat; she dreams of Naksu when she lived in the woods and trained. As for me, these are memories that Bu Yeon borrowed from Naksu in order to trick her own soul into being Naksu. Second: a dream in Master Lee's hut. In a dream, Mu Doek meets herself but the one that is hidden in her own subconscious, the real Bu Yeon. If the theory of two souls were true, then Naksu would see herself and Mu Deok, not two Mu Deok? !!! And there is also the question of her amazing knowledge, not only magical but also general. She is clever, articulate and well-versed in royal customs. I am not saying that Naksu has no knowledge about it, but would she have had such knowledge living alone in a remote forest? Third: there is no blue mark on Mu Deok's body that appears when the soul changes body. Fourth: the blue eye may be the source of Bu Yeon's birth since she died in the womb. Jang Kang bringing her back to life can be a blue eye signaling the soul's return to the body? What if Bu Yeon had never been blind, just covered her eyes because of their color, or maybe her mother had put a spell on her so that she would never know what happened?

 imagine:
n episode 1, Joo wol refers to the major four famile's childern as the four seasons. And Jin Cho Yeon is refered to as spring and is shown in front of a blossoming tree with petals falling down. 

If you returned to the very first couple of days in the comment section, you would see a post by SominahJ - who happens to have a Twitter page dedicated to Jung So Min.  In the post, she put forth the theory that Mu-deok was the missing Jin sister because of the cherry trees.  I also posted something about it (different theory, same conclusion).  So, you are right - the clues were there from the beginning.

 Ahead:
In EP 1, MD imagined killing Uk while he was taking a bath. If she only relies on the sword's energy, she is not someone impressive then. Her father was a mage who have reached Chisu cos Jin Mu said that only those who have reached Chisu can open the constellation ceiling.

Perhaps my point wasn't very clear but my theory is that because she gets energy FROM the sword (not water/earth/atmosphere), she is able to do mage-type spells.  She's the one who kept saying that she gets her energy from the sword - once her sword was returned, she was certain she would get her energy back.  

As for the constellation ceiling, I believe that was Jin Bu-yeon's power - a divine (from the skies) power that is truly amazing.  

Kathryn_51  & Izyda 

Why is Naksu so knowledgeable?
Her father was a mage who works at the constellation and he had reached Chisu cos only those who have reached 3rd stage can open the constellation ceiling.
Her father was the best friend of Jang Gang.
He probably worked at the palace and he was very knowledgeable.
Naksu was with her dad wherever he went.
Jin Mu probably taught her everything she needed to know and she might ask lots of questions and he might have answered them without realizing it. But she didn't ask anything about him cos he was the only one who took her in and she trusted in him.
So, she got all her knowledge from her father, Jang Gang and Jin Mu.
These are just a prediction so I could be wrong too. Believe what you want.


@DaisiesOh
Her Post Title: Alchemy of Souls: How Soul Swapping Works
Okay. I don't like how she says that people who don't believe her theories are blahblahbalh....
After reading that post, I thought again and got 7 points so far about why there are two souls instead of two personas, one soul.
I am not here to fight. I am going to stick with two souls and one body for now.
Believe what you want and pls don't stop writing theories cos you (everyone) might be able to convince me & others one day or not. Theories are interesting so don't be afraid to keep writing.
I am sure you aren't afraid to write cos you know...


 Izyda:
Second: a dream in Master Lee's hut. In a dream, Mu Doek meets herself but the one that is hidden in her own subconscious, the real Bu Yeon. If the theory of two souls were true, then Naksu would see herself and Mu Deok, not two Mu Deok? !!!

I think my number 5 point answered your question.

5. There was one time when Naksu looks like blindfolded MD in her dream, but I think it was because the soul was moulding into the body's image or she could go wild. Maybe.

Soul doesn't have a form which is just like water so I think the soul is taking MD's form now. Or is it a production mistake? Or I am wrong and we will get an answer later on.

 Kathryn_51:
Perhaps my point wasn't very clear but my theory is that because she gets energy FROM the sword

yup. She kept mentioning she will get energy from her sword cos her energy is blocked rn. That's what I think but you could be right too.

 Kathryn_51:
As for the constellation ceiling, I believe that was Jin Bu-yeon's power - a divine (from the skies) power that is truly amazing.

It could be anyone cos Naksu had reached Chisu long before and JBY's divine power can.

Mirror event and constellation event has the same pattern. JBY opened the energy for Naksu and Naksu used the energy. Then, she went blind for a moment. JBY probably did more than that but it doesn't matter to me as long as MD is safe. :D

But it would be good to know who did this and who did that.

 Ahead:
Believe what you want and pls don't stop writing theories cos you (everyone) might be able to convince me & others one day or not. Theories are interesting so don't be afraid to keep writing.

With regard to the one soul/two soul theories, I have no definite opinion and I'm not trying to convince anyone.  I posted the link to the DaisyOH because I wanted to at least give her credit for her theory because she appears to be the first one to spell it out.

I do have theories about  Jin Bu-yeon' soul and I think the statement by Cho Yeon regarding how divine powers are different from spell making powers was a significant piece of information.  

Myself, I'm still on the two-soul theory (though obviously no one can be sure...)

As I think jxxvvxxkstan suggested, the appearance of Naksu as (unblindfolded) Mu Deok  in the dream world could be explained by souls taking on the appearance of their current body (so Naksu appeared as Naksu when she soul-shifted  and Mu Deok when she dreamed; I guess Bu-Yeon still remembers her blindfolded state).

For a much wilder theory (please bear with me), perhaps it is Bu Yeon, not Naksu, who's trapped in Mu Deok's body. It's Bu Yeon who acts as if she is trapped, only able to emerge in times of extreme stress. This would require Naksu to possess Jin-type priestess powers (which IIRC are sufficient to trap even the most powerful mage).

There's no doubt Naksu was very powerful, and maybe there are things still unknown about her origin. (I doubt she learned all her knowledge about magic from her father or Jang Kang as a young child, and I doubt that Jin Mu would be so forthcoming. Also how did she excel in isolation without some intrinsic magical abilities, like Jang Uk or Bu yeon?) So perhaps Naksu was capable of trapping Bu Yeong and somehow (unintentionally) selected Bu Yeon, rather than the other way round.

On some other forum, I saw a poster observe that just before Master Lee was about to kill Mu Deok in the hut, he stopped and said something like "a powerful soul has shifted into this body."  If we take this comment literally, that soul wasn't Bu Yeon because we now know that  she's in her original body (unless it referred to Bu Yeon soul-shifting at birth). So that powerful soul would have to be Naksu.

(Ok, maybe I'm giving the Hong sisters way to much credit here! I suspect a deluge of plot inconsistencies may be pointed out once the series completes. )

 Kathryn_51:
With regard to the one soul/two soul theories, I have no definite opinion and I'm not trying to convince anyone. I posted the link to the DaisyOH because I wanted to at least give her credit for her theory because she appears to be the first one to spell it out.

Yeah. My bad. I sometimes read too much and thought of their intention. For you, you just want to share your ideas which is good. Giving credit to the owner is definitely a good thing to do unless you don't know her and figure out it yourself. Then, you noticed that someone has already posted it and laughed it out cos you aren't the only one who thought the same. ?


 Kathryn_51:
I do have theories about Jin Bu-yeon' soul and I think the statement by Cho Yeon regarding how divine powers are different from spell making powers was a significant piece of information.

Yeah. Cho Yeon gave us the reasons why Naksu can't use her power not just because she shifted her soul but cos of the divine power too. She didn't think much about those events (Mirror, AoS, dizziness at Jinyowon & etc...) cos divine power can erase memory too.

Yeah. I am exaggerating a bit. ??

Here are a few more points on why I stick to 2 souls+one body (MD).

8. Bu-Yeon was still a baby when Naksu’s dad was killed (20 years ago). JBY got lost in the river after 10 years. They both don’t have blue marks*.

9. The soul is the one that carries energy/divine power. That’s why the old man did AoS and still got his energy fine. Master Lee still got his energy even after going into the dead little boy. If JBY did AoS on anyone, they would go blind automatically cos of her divine power.

10. This is kind of cheating cos this will be based on a rumour of part 2. Naksu’s soul will return to her original body. JBY will be left with MD.

@nosnoop said, “The Korean title 환혼 (Hwanhon) literally means Return of the Soul; but it should mean more like Resurrection in this context. But if you just put it in Google Translate, it would give different translation as it can mean different things in different context.”

“Resurrection?” – Resurrect Naksu’s body?

 Thecla:
Also how did she excel in isolation without some intrinsic magical abilities, like Jang Uk or Bu yeon?)

Could you please explain by isolation? I haven't seen Naksu uses any isolation spell.

 Thecla:
If we take this comment literally, that soul wasn't Bu Yeon because we now know that she's in her original body (unless it referred to Bu Yeon soul-shifting at birth). So that powerful soul would have to be Naksu.

Yeah. I have a hard time thinking about whose energy it is. It could be JBY's divine aura or it could be a strong mage aura which is Naksu's. I am still not sure. ??

 Ahead:

Could you please explain by isolation? I haven't seen Naksu uses any isolation spell.

Yeah. I have a hard time thinking about whose energy it is. It could be JBY's divine aura or it could be a strong mage aura which is Naksu's. I am still not sure. ??

No, no! I just meant that Naksu was totally isolated in Danhyanggok when she developed her skills, and how could she have reached the level  that she did without some kind of inborn ability? Say from her father, or perhaps her mother about whom I don't think we know anything. (She could be from the Jin family?) I wasn't suggesting that Naksu's skills involved any isolation spells.

I do think the default position is that Mu Deok's blue aura is from Bu Yeon (hard to see Naksu as someone whose "soul has no malice") even though Master Lee's comment that "a great soul has shifted into this body (18:00 Ep 5) seems to cut against this.

 Thecla:
Naksu was totally isolated in Danhyanggok when she developed her skills, and how could she have reached the level that she did without some kind of inborn ability?

It took her about 20 years in total to get to Chisu. I don't know. They never mentioned when did she reach Chisu. I think that's pretty long and I think she got it cos she was persistent or there was more to how she got that level.

 Thecla:
Master Lee's comment that "a great soul has shifted into this body (18:00 Ep 5) seems to cut against this.

Yeah. It makes sense. It is more likely to be Naksu's.

 Thecla:
I do think the default position is that Mu Deok's blue aura is from Bu Yeon (hard to see Naksu as someone whose "soul has no malice") even though Master Lee's comment that "a great soul has shifted into this body (18:00 Ep 5) seems to cut against this.


 Ahead:
Master Lee's comment that "a great soul has shifted into this body (18:00 Ep 5) seems to cut against this.
Yeah. It makes sense. It is more likely to be Naksu's.

Thecia and Ahead,

I analyze this based on everything that Master Lee says.  In fact, it is his words that are the best argument  to the theory that Naksu=JBY.  He only sees one soul.  That's not the final word (there may be a good reason why he doesn't see two souls) but to me it's the strongest argument for that theory.

He sees a "great soul".  But other than the scene on the cabin porch, he hasn't seen JBY/Naksu's powers manifest.  He's trying to figure out who she really is and why, if she was Naksu the Assassin, she has no power.  He also has no idea that Mama Jin has a missing daughter who had divine powers.  He wanted the poem housed at Jinyowon - I think he suspects that there is a connection between "Mu-deok/Naksu" and the Jin family (as I mentioned earlier, perhaps Cho Yeong's mother was a Jin).  

I just want to see Jin Bu-yeon (hopefully portrayed by Jung So- hope min) as a stand-alone, cognizant woman blasting her divine powers out at the bad guys.  So-min said that she had a week of pretty physical filming - I hope it wasn't just some of the scenes (in the water, in the "soul realm"  early boat jumping) we have already seen.  

 Kathryn_51:
In fact, it is his words that are the best argument  to the theory that Naksu=JBY.  He only sees one soul.

Well, Master Lee just says he sees a great soul in Mu-Deok. It's not clear to me this means he didn't see any other souls (unless there's other evidence of that).

I actually don't understand the one soul theory (no doubt explained in much more detail elsewhere!). Is the idea that Naksu's soul was Bu-Yeon's soul (even though Mu-Deok definitely has Bu-Yeon's body). Or is it that the souls somehow merged when Naksu shifted (we know Bu-Yeon can prevent AoS removing a soul from a body). Neither of these seem easy to explain. Although to be fair the idea of two souls occupying the same body also seems in conflict with what we know about AoS.

Or going even further, could Bu-Yeon's soul have shifted into Naksu's body and remain there? Given her powers, she could perhaps survive in a dead body and even communicate with and pass energy to Naksu/Mu-Deok through the soul/dream realm.

I still think is likely that Naksu's actual body wasn't burned (perhaps rescued by Seo Yul), mostly for meta-story reasons. Suppose (purely hypothetically!) that Naksu returns. It's completely in line with established mythology that AoS could bring her back to life by summoning her soul  back to her body (we're told explicitly at the start of Ep 7 that the soul ejector can do this) .

On the other hand, we've seen nothing to suggest it's possible to reconstitute a body that's been burned to ash (the sorcery is all about swapping souls between bodies, not recreating bodies). If that happened, it would be a pretty unsatisfying deus ex machina (some extra-special Jin item or something) as the explanation for Naksu's return.