Peter Ratri (ピーターラートリー,Pītā Rātorī?) is the 36th and current head of the famous Ratri Clan and the younger brother of James Ratri. He is also the main antagonist of the series.
Peter is a by the books no nonsense kind of person, as demonstrated when he had several humans executed for being labelled as traitors. He is also someone who is willing to sacrifice others for the sake of keeping the promise.
The two of them originally had a good brotherly bond. Peter even agreed with James his way of thinking for a while because he thought that it was better. This seemed to be a facade when Peter revealed that he was just pretending to agree with James' plans. Peter even went as far to take James his title of the 35th head of the family and claim it himself. He then ordered his underlings and the rest of his clans to kill his own brother, implying the hostility between the two.