Ok, I Really Want To Talk About This Scene In Particular, And How The Different Phrases In English Bring

Ok, I really want to talk about this scene in particular, and how the different phrases in English bring out certain nuances:

The unofficial manga translation is the most accurate, as @akumadeenglish went over in their post. While in Tango on the Campania, the line used in this scene became "I promise I'll protect you, at any cost!" Now, translations can't be 1:1 all the time, so long as they get across a similar intention from the original language they're good. But I want to emphasize the difference between "protect you at least," and "at any cost," and what they imply.

"Protect you at least," can be taken as foreshadowing, as we find out later Ciel had a brother that he lost. So the words "protect you at least," implies that now, out out everyone alive, it has to be Lizzy that survives. It makes sense, as Ciel naturally sees her apart of his family when he remembers his happy past, almost like a set (even more frequently than Madam Red surprisingly).

However, "at any cost," is far more foreboding. Because it's what Ciel told Sebastian, at any cost he wanted "more power than anyone else". That's why I assumed Sebastian laughed when he heard him. Would Ciel really do it for any cost? Even if it's at the cost of his revenge? When I first read it, I assumed it implied that Ciel would be tested by those words and genuinely got worried that Lizzy really would die to the bizarre dolls. Even now I'm still concerned what price will be paid in the future...