Responses
it's a good theory,but undertaker clearly said that it's not the time to wake up so for now this is Ciel,but i think that Sebastian and Ciel know who undertaker is talking about,because when they come from germany juste after the story about the visit of Undertaker they have an idea,but the author didn't tell us -.-
I was wondering... Maybe the one who woke up isn't Ciel? Maybe his brother (if he had one) or Vincent? Because Undertaker said "It's too early to wake up". He'd wake up in that moment according to his plan, and that's why the symbol wasn't in his eye, because the soul wasn't the one who did the pact. When he was aware of what was happening, he covered up his eye and did something to show the symbol.
Huh... Does it make sense?