Yes, my Lord

One song of Sebastian Michaelis.

Sebastian Michaelis.

Black and White

The song of Ciel Phantomhive and Sebastian Michaelis from the musical of Kuroshitsuji II

Ciel Phantomhive and Sebastian Michaelis.

Red or Black

The song of Grell Sutcliff and Sebastian Michaelis from the musical of Kuroshitsuji I

Sebastian Michaelis and Grell Sutcliff.

Shinigami Dispatch Department

This society handles to dispatch of Shinigami for reaping souls. They decide who should continue to live or not based on their history.
We can see that there are new main Shinigamis that were shown in Kuroshitsuji Musical 2: The Most Beautiful DEATH in the World. They are Eric Slingby and his best friend Alan Humphries. We all know that Shinigami must follow rules but one of them secretly didn't follow the rules like Eric Slingby who kills/collects a lot of people/souls in London in order to save his best friend Alan in his illness named "The Thorns of Death" which can only be heal by 1000 souls.
When William along with Ronald knew this he decided to punish Eric but Alan stopped them.
Later, Alan found Eric and asked him to stop running. He said that he will kill his self if he didn't tell him why his killing a lot of people who aren't in the death list. Eric rushes and stop Alan then Eric told Alan that his doing this to heal his illness because he doesn't want to loose Alan. Alan forgives Eric and decided to take off their glasses as a sign of resignation as a Shinigami and run away and forget everything. Alan also made Eric promise that he will not kill anymore.
While they are running, Alan was attack again by his illness. Then Sebastian came and tell everything to Eric that what he would have done is useless. He's also there because Ciel ordered Sebastian to kill Eric but Alan stops Sebastian as Alan begs Eric to stop. Then Eric attempts to kill Ciel Phantomhive, Alan steps into his path (because Eric had promised earlier not to kill anymore) and is killed by Eric's death scythe. Eric is deeply upset, but Sebastian Michaelis ends his grief by killing Eric with Alan's death scythe. When Eric is killed, the souls that he had collected for Alan were released, falling like snow around Sebastian and Ciel, creating "the most beautiful death in the world."

Eric Slingby - Character

Eric is shown to be brave, caring, and serious by breaking the rules of not killing humans just to save Alan from his disease. He also seems to be a hard worker, but he is also laid back. As Ronald hinted at in the second musical, Eric appears to enjoy parties. He also likes to tease Grell when Ronald requested Grell to resign he said "I bet everybody would be extremely happy.".

Alan Humphries - Character

Alan Humphries is a member of the Shinigami Dispatch Department. He works directly with Eric Slingby, William, Ronald Knox, and Grell Sutcliff. Alan seems calm most of the time, but can become angry and shout. Like the other Shinigami, Alan has little tolerance for those who break the rules or slack off. His Death Scythe is a Japanese-style long-handled garden slasher.

Alan plays a major part in the second Kuroshitsuji musical. He is revealed to have an illness named "The Thorns of Death," which can only be cured by collecting one thousand souls. Alan, despite his illness and his frequent attacks, participates in the hunting of his partner, Eric Slingby, who is thought to be killing random people simply for his own pleasure. He even disguises himself in a dress in order to find Eric at the opera scene.
After Alan confronts Eric, it is revealed that Eric has been collecting these souls in an attempt to save Alan's life, stating "I would commit any sin if that allows me to share your pain." Alan appears to instantly forgive Eric. The two agree to run away together, after Alan makes Eric promise not to kill anyone else. They both remove their glasses, which signifies their resignation as Shinigami.
At the end of the musical, when Eric attempts to kill Ciel Phantomhive, Alan steps into his path (because Eric had promised earlier not to kill anymore) and is killed by Eric's death scythe. Eric is deeply upset, but Sebastian Michaelis ends his grief by killing Eric with Alan's death scythe. When Eric is killed, the souls that he had collected for Alan were released, falling like snow around Sebastian and Ciel, creating "The most beautiful Death in the World."

Undertaker - Character

Undertaker seems to take joy in frightening others, as he seems to act creepy intentionally to provoke a reaction. He seems to enjoy both his job as a funeral director and as an informant to the Phantomhive family, as he has worked with them since before Vincent Phantomhive's time. He has great connections with the underworld, as victims of murder from the underworld often show up at his place of business. It is these connections that allow him to be a useful informant to the Phantomhives. However, he does not exchange his services for "the queen's money," as he seems to dislike Queen Victoria. Instead, those who want information from him are expected to amuse him in some way.
Known only by his profession, the Undertaker is a mysterious man whose scarred face is never fully visible beneath his long hair and crooked top hat. He occasionally provides information to Ciel. While he finds Ciel amusing and enjoys helping him out, he has nothing but disdain for the Queen. He tends to punctuate his words with sweeping gestures and creepy giggles and seems to spend a good deal of time inside of coffins.
He frequently refers to the deceased as his "guests." It is his hobby to remove organs from his "guests" for research. When living people come to visit him, he frequently asks if they came to see what it feels like to sleep in a coffin. He is shown snacking on bone-shaped biscuits and drinking tea from a beaker.