Number 48
from Fullmetal Alchemist: BrotherhoodSupporting
The Slicer Brothers are a pair of serial killers who become one of the guardians of Laboratory 5 under the joint alias of Number 48.
About Number
The Slicer Brothers are a pair of serial killers who become one of the guardians of Laboratory 5 under the joint alias of Number 48. They had their souls bound to a single suit of armor by way of a pair of blood runes (one in the helm and one in the armor's neck piece) and were assigned to kill any intruders at the laboratory.