As proposed on Friday, here’s a recap post about my take on it, for the few who wanted it and in hope that it might help some others with the few misunderstandings I’ve seen going around. Let me know if anything is not clear!

First thing first, despite the name of the theory, real!Ciel isn’t exactly the mastermind or the real target of Ciel’s revenge for me, if just because he and our!Ciel wouldn’t have ended up with child traffickers and sold to the cult if there wasn’t another party involved (and wanting for them to suffer). 

So someone else definitely manipulated real!Ciel and his possible wishes, in order to get to the Phantomhive household. They sent someone, very probably a supernatural being considering how they appeared right behind our!Ciel, to kill almost everyone before making sure the boys would know Hell.

For simplicity’s sake and this post, we’ll assume the true mastermind is Queen Victoria (+ John Brown) and if there is a need for more explanations, please check these posts [x][x].

Moving on, in my take of the RCMT, there were only two attackers on December 14th: 

and while #1 is the supernatural being (Brown?), #2 is real!Ciel (see below). 

However, I know, why would a ten year old child ever wish doom on his own family? 

Well, first of all, things very probably didn’t go according to real!Ciel’s plan, way before the boys were even given to child traffickers: I’m of the opinion that initially all that real!Ciel ever wanted was for his father to die.
And why? Because with Vincent dead, he was the next head of the Phantomhive family and as such…

…he might have a say into his little brother’s project to go to London and become a toymaker, leaving him behind. 

But things escalated from the twin’s initial plan, very probably because of the real mastermind who used real!Ciel’s little wish to get his father out of the way to almost entirely annihilate the Phantomhive household, before getting rid of the twins in a much crueler way

(possibly because real!Ciel was an accomplice). 

So overall was it a horrible, irrational and childish idea coming from real!Ciel? Well, yeah, but he was ten years old and, mostly…

he apparently had (& still has as a bizarre doll) a rather pathological attachment to his little brother

(bordering on obsession really) and that could be enough of a reason for him to truly fear the future separation. 

He might have even seen his parents as being unsupportive of him and his issue on the topic, because they clearly seemed to be okay with our!Ciel’s choice in ch133. Thus getting rid of at least Vincent to replace him and have his say on the matter was a minimal price to pay for not being separated from our!Ciel.  

I disagree with fans labelling real!Ciel a psychopath in the past (it’s possibly different now because of UT), however I do think something was wrong with him if his little brother was the only one who mattered above everyone else to him. And, again, I really think that’s the case because…

(”together” as “just the two of us”)

…Lizzie, the Midfords, Ann (before she died)? Well, he didn’t/still doesn’t seem to consider them at all. :// Our!Ciel does though…

and that’s from where I draw a comparison between what’s normal and what seems to be less so, because it’s as if Sensei wanted to insist that they’re very different on this point. 

So, looking at ch133/134, what happened?

First of all, it’s very important to realize that there is a one and half year time skip between real!Ciel breaking down about our!Ciel leaving him behind (with Vincent and Rachel not taking his side) and December 14th, 1885. 

And it’s important because that means that Sensei purposely hid what the twin did or even how he acted between the incident and the actual massacre, after focusing for two chapters on real!Ciel being bothered by his brother leaving him. 

So “he was a sweet kid, loved his parents and he would have never done that”? Well no one can know that for sure, since it’s not like we really saw anything about him between “I have no choice but to become Earl Phantomhive” and the attack on the manor. Besides, it’s kind of very Sensei-like to do foreshadowing this way, just saying.

Moving on, I’m not going to expand on how/when/why real!Ciel could have ended up as an accomplice of the attack of December 14th because we have no clue of that yet (that’s all in that one and a half year missing from the flashback), however I think everyone pro or against RCMT realized by now that the outsider who killed almost everyone received help from inside the house.

That helper is real!Ciel for me: he’s the one who muzzled Seb the dog and locked him in, so that he wouldn’t warn anyone/attack the intruder, but also maybe so that he wouldn’t be killed.

As I said above, I doubt that real!Ciel considered that anyone besides his dad had to die for him to get what he wanted and both the dog and servants could still be useful to him as the next Earl

anyway

(in order to keep the exact same household, except for Vincent himself). 

As for Rachel, well, from the way she and Vincent died, embracing each other…

…I think she tried to shield Vincent and was killed first. ;_; 

However,

had his initial plan gone perfectly, I’m not sure either that real!Ciel thought it necessary for his mother to die (just like the dog and servants). 
Either because he imagined that, once he’d be Earl, a woman would have no way to stop his decisions (I mean, look at what he said to Lizzie, I know he was a kid but ://), or because he thought she could understand after what she said about her and Ann in ch133.

There again, real!Ciel’s plan definitely didn’t go as expected, since the real target of our!Ciel’s revenge ordered her assassin to annihilate the whole household instead (the twins awaiting another horrible fate), which…

is

what 

took 

place. Well, almost because someone survived.

Before I get to this part though, I have to say: I don’t think real!Ciel is the one who killed his parents. He wanted his father dead, yes, but he’s not the one who stabbed them, or Seb the dog, or even most of the household. 

Just look at ch134, all the dead people our!Ciel came across had a lot of blood pooling around the bodies, a lot of blood on the walls or furnitures around too, which in my opinion signs the work of a real skilled killer (that supernatural being, attacker #1). 

So I doubt the twin would have been able of that, not at ten years old, not when he didn’t have blood on his clothes and not when he seemed to suck at fencing. What he did do however is at least muzzle and lock the dog, take the Phantomhive ring from his father’s hand (the ring that proved he could inherit the position after his father)…

and possibly stab Tanaka at least once (making him attacker #2). 

The reason I think the twin is the one who stabbed Tanaka is the opposite as to why I think a real pro took down everyone else: Tanaka was stabbed twice 

meaning that the first time wasn’t enough to kill him, so:

• either he held his own against a supernatural being because he was strong enough 
• or real!Ciel is the one who wasn’t skilled enough to kill him on the first try. 

Also, the second time Tanaka was stabbed was precisely as he attempted to warn our!Ciel of something about real!Ciel…

And if real!Ciel was in on the plan about December 14th, frankly I doubt he’d want his little brother to know that he was an accomplice in the massacre that took place. 

The last chapter even implied that servants aren’t exactly people real!Ciel tends to care about anyway…

…so who knows if even Tanaka wouldn’t become disposable from the moment he caught on about real!Ciel being an accomplice? ://

So basically, real!Ciel is the one who stabbed Tanaka in the back, just as Tanaka tried to warn our!Ciel, but then the supernatural attacker showed up and took our!Ciel away before he could see who was the one with the knife. 

I know Tanaka is still considered as a suspect by some fans, but honestly I just can’t see how or why. And when it comes to how Tanaka managed to survive his wounds and the fire that destroyed the whole manor, since that’s one point making him suspicious, I discussed it a little here for those interested.

Additional hints & details for the RCMT

To tie with the more recent chapters, since UT brought back the twin, but not mandatory when it comes to understanding the theory, so under read more: 

the twin’s behavior towards our!Ciel

I think it’s a hint by itself, because he still seems very obsessed with the idea to finally “be able to be together forever”. 

Real!Ciel being a bizarre doll though, that means UT brought him back through editing his cinematic record with “episodes” (i.e ”yearning for the future”).

In other words, if before he died real!Ciel was strongly envisioning his future as “being together forever” with his little brother (as the flashback showed well enough), it could explain why he’s still super obsessed with the idea, because that’s literally what keeps him going as UT’s current masterpiece. 

A real obsession can be dangerous: look at Ann and the JTR arc, or look at UT who can’t mourn the dead Phantomhives and instead tries to bring them back through lots of horrible and bloody experiments. So in real!Ciel’s case, it’s not that impossible that it could have led to December 14th. 

the attack on Soma and Agni

Could be a hint depending on why the twin became violent and what was the purpose of the twin coming to the house in the first place.

• Was it to see our!Ciel? And that’s why they wrote a creepy message on the wall? In that case, discovering Soma living there or Soma acting familiar with him triggered his violent reaction.

• Or was it because of Soma himself? It’s obvious that UT told real!Ciel about what life his brother led for the last 4 years, so he could have mentioned Soma. However, considering how real!Ciel only sees and cares about him and his little brother, Soma calling himself “Ciel’s big brother” could have made him super jealous. ://

why did the attack happen on December 14th precisely?

In case anyone else is wondering. I’ve seen three possibilities until now: 

1. because it was easier for the twin to get everything ready (muzzling the dog, etc) while everyone else was otherwise busy preparing their birthday party. There is even a mention of real!Ciel reading till super late the night before, to the point of not getting enough sleep. 
2. because, in the idea that real!Ciel was really missing some screws, the plan to kill his dad so that he could become Earl was supposed to be a birthday gift to both him and his little brother (since the plan was one way for them to “be together forever”) (proposed by @asthmaticastre​ [x])
3. rather than being related to the twin, the choice of the date is related to the mastermind, because Prince Albert was Queen Victoria’s love of her life and historically he died on December 14th, 1861.
   So if in Kuroverse the Queen thinks her Watchdog at the time (Claudia) was somehow responsible… she could hold a grudge => short version of the theory.  

could someone have prevented the RCMT from happening? 

Because I remember that a lot of readers used to despise Vincent and Rachel for “badly raising their son” and not paying attention, but I just don’t think it’s their fault, because I don’t think that real!Ciel behaved particularly oddly aside from that one trait.

That being said, as I explained here, I think there is a slight possibility that Vincent might have caught on about his first son’s strong (rather abnormal if the rcmt is a thing) attachment to his little brother… 

Not that it saved him or Rachel, so I guess no one has to care, but we’re still missing one and a half year from the flashback and, in general, Vincent is a rather mysterious character so… in case we ever address that time skip again, it could be useful to at least consider the idea. 

why would UT even bring back the twin if the RCMT is true, considering how much he cared about Vincent?

Last point, but at the heart of the current arc and I agree with @dorkshadows on the matter, which is to say that UT is so biased obsessed with not wanting to lose more Phantomhives that he would probably find every reason to excuse real!Ciel’s involvement in what took place on December 14th.

Though there is also the possibility that UT didn’t even watch this part of the twin’s cinematic record before editing his record post credits, because he was already convinced that the Queen was behind the attack on December 14th. In that case he wouldn’t even know that the twin played a role in Vincent’s death. 

---

I’ll conclude by redirecting you to what @cielsama14 once said about the RCMT here, which I think is extremely fitting, especially considering what Sensei always said about the P family being cursed.

Long post as always with me, but I hope it was understandable!

Please keep in mind that this is my take on this theory, but there are other versions.
Don’t hesitate to ask if there is anything. Thanks for reading. 🙂