The Bordanian Monks are an exceptionally obscure order of Roman Catholic monks whose mandate is somehow tied to the Supernatural Prison at Castel Sant Angelo. It is unclear exactly what abilities if any that may possess, but their presence at the prison may imply that they possess some significant abilities.
The monks appear to have taken a vow of Silence as they have not been heard to speak, instead gesturing to visitors at the prison.
It is clear that they are involved in the intake of visitors, and apparently also the inspection of those same visitors as they depart the prison. It is possible that they possess some sort of enhance sensitivity to supernatural energies or possess some sort of enhanced vision or smell.
They were first encountered at the Prison in 1936, by members of the Vatican City Save Office.