Black Butler 2 cannot exist for many reasons. For one reason we have followed Ceil Phantomhive since the beginning and has never left his side. Sebastian has never left his side either. Even when he left he was always with someone. It is also proven multiple times in the show that Sebastian can feel when Ceil in immediate trouble. It can also be assumed that when Sebastian was taking Ceil to the area where he was going to swallow his soul he never left his side. In all that evidence, Claude could have never have enough time to swallow his soul and leave with enough time to find a sufficient enough hiding space. Plus, even when Sebastian left his services, we never went with Sebastian, but with Ceil, following his every movement. There was no way that Claude was able to swallow his soul. When Ceil was sitting down waiting for his soul to be swallowed he said right before that to make it hurt. If his soul was not in his body then how could he have said that with as much emotion that he did.

If they were planning to make a sequel, then they could at least hinted or shown Claude and his master, Alois. But if they weren't planning to make a sequel then they could have at least done a story or arc from the manga, like they did for the third installment for the series. Instead they did a train wreck of a show with sub-par characters and ruining the franchise for four years. Even the episodes of Black Butler 2 that I did enjoy a little, were very sub-par for this show and franchise. There were some ways for this show to be great or at the very least good. First, have the sequel either have a villain that was relevant in the first show, like have a new grim reaper be the villain. Or introduce the villain to be someone we never saw before, but was mentioned in the show earlier. Like Elizabeth's mom or dad since we didn't see them in the original show and when we saw Elizabeth out she was with her nannie. But never with her parents, so could that be an interesting twist. Or like I said earlier they could have done an arc from the manga instead of what I believe is their own original story.

So in conclusion that is why Black Butler 2 cannot exist or should not exist. If you are a new fan to this series and enjoyed and loved the characters of Black Butler then don't watch this sequel. But I do suggest Black Butler: Book of Circus.