The Butler, A Colleague (その執事、同僚, Sono Shitsuji, Dōryō) is Chapter 26 of the Kuroshitsuji manga.
Sebastian and Ciel's stage names are revealed to be Black and Smile, respectively. Joker takes them on a tour of the backstage, pointing out the second-tier members' tents, mess hall, storeroom, first aid tent, and the private tents for the first-tier members, guarded by Snake's poisonous snakes.
Sympathetically, Joker questions what happened to Ciel's eye. Sebastian asks if everyone joined while the Noah's Ark Circus was on tour, to which Joker replies that the first-tier members, except for Snake, all came about from the same hometown, but everyone else did. They let Snake become a first-tier member, though, since they did not have a snake handler before, and he is quite skillful. Joker points out that becoming a first-tier member is good because you get your own private tent and do not have to worry about competing with the other second-tier members, and encourages them to work hard.
Finally, he shows them to the practice tent and leaves them to warm up and start practicing. Sebastian and Ciel mull over what they have learned while they stretch, and Sebastian points out that the kidnapped children are not present. Dagger takes notice of them, telling them to hurry up. He asks them what sort of performance they would like to do, and decides to teach Ciel how to be a dagger thrower. He encourages Sebastian to try a lot of things, which he does with zeal, succeeding at all of the activities he tries.
Everyone fawns over his skill except for Ciel, who wants him to fit in more. Dagger then reveals that another "super newcomer" is present and introduces Suit, who is actually a Grim Reaper, William T. Spears. William proceeds to attack Sebastian, calling him a demon. The other circus members are confused and surprised, and Dagger decides he must be joking. He encourages them to bond, but William dismisses Sebastian as a "savage beast". Ciel is encouraged by his presence, certain that it means something is amiss with the circus.
Sebastian approaches William and takes him outside to talk. William initially refuses to release any information to Sebastian, calling him a starving demon. Sebastian says he has no interest in poor-quality souls and reveals the symbol of his contract, saying he is "collared." William accepts this and reveals that a large number of individuals are expected to die in a few days. Sebastian takes advantage of William's dislike for him, teasingly offering to help him with the souls. This prompts William to attack him with his Death Scythe.
Ciel interrupts, and William begins to comment that Ciel is not high-class goods, which upsets Ciel. As William points out his lack of understanding of demons, Ciel stops him there. He tells William to stop blurting out both his and Sebastian's true identities so carelessly and casually. He states that they were fortunate that everyone believed him to be joking, but if he keeps this up, he might arouse suspicion among them. William's failure to blend in could put their investigation at risk. Ciel further berates him for his lack of subtlety, declaring him to be lower than Grell. They agree not to interfere with each other.
Back in the practice tent, Joker reveals the room assignments and places Ciel with a second-tier member named Freckles. Sebastian is paired separately, much to Ciel's dismay, with William. Dagger states that this is great because they are already such good friends, telling Ciel not to stick so close to Sebastian and to make new friends. William and Sebastian are decidedly unhappy about the arrangement, while Freckles warmly greets Ciel.