On Christmas Eve, four-year-old Miri Unasaka arrives in Tokyo completely alone, in search of her father. The bright lights and merry atmosphere guide Miri to a big hotel and a man with a delicious-looking cake. However, the child has just unknowingly walked into the center of an elaborate, foolproof plan for assassinating a dangerous mafia boss. Professional assassins Kazuki Kurusu and Rei Suwa live together, fleeing memories of their grim childhoods and avoiding emotional connections. When their mission goes awry and they end up bringing Miri home, there is only one reasonable thing to do: return Miri to her mother. But the girl's innocent laugh and pure worldview quickly enamor her to Kazuki, who secretly enjoys playing a parent, and it is not long before Rei's impenetrable heart makes room for Miri. Miri's every move is unpredictable, and Kazuki and Rei find raising an energetic child harder than any of their missions. Although it presents a great risk to their careers, Kazuki and Rei—both assuming the affectionate nickname papa—decide to provide Miri with a normal childhood despite all the odds stacked against them.

A short OVA that was bundled with the limited edition of the eleventh volume of the manga.

Mafia is rife in America where assassinations are a regular occurrence on the streets. Inferno, a mysterious company, is behind most of these dealings through the use of their near-invincible human weapon, Phantom. One day, a Japanese tourist accidentally witnesses Phantom's latest murder. Desperate to escape, the tourist hides in a secluded building. However, Phantom, revealed to be a young woman named Ein, and the leader of Inferno Scythe Master captures the tourist and brainwashes him. Given the name Zwei, this once peaceful tourist is now a puppet of Inferno with no memories. Drawn into a world of lies, deceit, and violence, Zwei must fight to survive, hopefully to one day regain his memories and escape from this world where he is constantly on the brink of death.

At the behest of the Queen, Earl Ciel Phantomhive hosts a lavish dinner party attended by several of the finest members of polite society—as well as struggling author, Arthur. But as the party reaches its high, a terrible murder takes place and none other than the Earl himself is suspected of the crime. As a violent storm rages on outside, the death count continues to climb. The Phantomhive household and their eminent guests find they must cooperate in order to solve this mystery before they too fall prey to the mysterious murderer. However, it seems that not even the perfect butler, Sebastian Michaelis, is safe from this horror.