The 2nd of the Fatui Harbingers, known as "The Doctor," wearing a mask that covers his eyes shaped like a bird's beak. He has light blue short hair and possesses a genius intellect that surpasses all of humanity. He has a history of being expelled from the Sumeru Akademiya in the past. He is the original developer of the elixir of immortality and the only human who still knows its manufacturing process. He is estimated to have lived for over 500 years. He is in a master-servant relationship with Pantalone. He obtains most of his experimental funding from Pantalone. He has narcissistic and psychopathic tendencies, characterized by a mocking laugh. His eyes are red, though he rarely reveals them. He has committed various atrocities, such as kidnapping over 40 children, ruining people's lives entirely, and nearly plunging the world into disaster. Even within the Fatui, his reputation is poor. Besides ordinary scientific knowledge, he seems to be well-versed in artistic fields. It appears he studied art specifically because the Akademiya did not favor the field of art itself. If he likes someone, just as he does not fear death, he will accept and express it in his own way. He will never deny it.