Noblesse
Cadis Etrama Di Raizel is the one True Noblesse, and as the Noblesse, Rai has the responsibility of protecting Nobles from external threats, but his main duty is to make sure that the Nobles do not misuse their powers by harming the humans. This gives him an authority to kill any Noble at his will. However as the noblesse, even though he has immense power, each time he uses his magnificent power he loses a part of his life force.