Something rather odd occurred to me earlier today. A lot of theories put Undertaker as the main antagonist of the series, yet the number who know he might be a threat is minimal. Of course Sebastian and Ciel know along with the shinigami. Other than them, the only ones who are alive who might have any idea are (possibly) Druitt, and those in attendance of the Midnight Tea Party - which is basically the S4 and the F5 minus Soma. Everyone else has no real idea, and Ciel isn’t the kind to talk. What makes this interesting is that it opens up quite a few possibilities.
Prince Soma and Agni:
I had to ask @midnight-in-town if they had even really met Undertaker before, and she reminded me that they had at Sebastian’s funeral.
I had to choose that picture. LOL. Anyway, this is the only context Soma and Agni have for Undertaker - as nothing more than an undertaker. They wouldn’t see him as a threat. Which brings us to the carriage in chapter 126.
A lot of people have pointed out that the driver could be Undertaker because there appears to be long hair and a hat. Now, I truly doubt that the shooter could be Undertaker because it seems odd for him to use a gun, but this isn’t to say he couldn’t have been a frequent visitor.
As far as Soma and Agni know, he’s an undertaker and nothing more. At worst, they might find him a bit creepy. Plus, if he said that he had known Ciel’s family for many years, Soma would have been eager to talk to him. Soma would have welcomed in someone readily that could be a potential threat because he had no reason to fear Undertaker.
While Lizzie was on Campania, she wasn’t there when Undertaker revealed his true identity. Like Soma and Agni, she has only known him as an mortician. In fact, she has had more contact with him because of other funerals. She would have no reason to fear him.
Edward does know more because of what happened at Weston, but it’s doubtful he shared this information with his family. How would you tell your family that an undertaker had played the part of principal at your school and dead students had been brought to life? More than likely, Undertaker has closed his shop, so Edward didn’t think about him being a danger, so Lizzie is still in the dark.
Undertaker could provide a familiar face and comfort to Lizzie all because she has no idea he’s more than anything he appears.
Sieglinde has never met Undertaker at all. However, she is the curious sort. If she knew of his (former) profession, she’d probably be very curious about embalming and working with corpses in general. He could also claim to be an old friend of Ciel’s, and she want to know more. Wolfram would be less trusting, but he might allow Sieglinde to invite her new ‘friend’ in. Could Undertaker benefit from this arrangement at all?
While the servants watch over the manor while Ciel is away, they are protecting from potential danger. Unless Ciel specifically said to watch out for Undertaker, they might not see Undertaker as a threat. They’ve seen him as an undertaker, and he might be able to gain access to the manor by saying he needs to talk to Ciel.
So, what does all this mean? Well, we’re not certain of Undertaker’s motives just yet. While he seems to be trying to protect the Phantomhives, albeit in his own way, we don’t know why or his end goal just yet. Because there’s enough people in Ciel’s life that don’t know, this creates places where Undertaker can get close. He might be able to gather new information or set up another scenario to face off with Sebastian.
What she means:
Was Soma really shot? Or was it Agni? Either way, one of them is dead. Did Ciel really let this happen? I trusted him! Who was in the photograph that distracted Agni? Who would do this to us? Was it Lizzie? Was it Ciel? That doesn't make any sense! Can 2CT really be true? We don't know anything yet. We just have a glove, blood, and a burnt photograph to go by. Nothing's set. Sebastian, can you pull off one more miracle and stop all this??
“Would you tell me, please, which way I ought to go from here?" "That depends a good deal on where you want to get to." "I don't much care where –" "Then it doesn't matter which way you go.” ― Alice in Wonderland