The Chief Justice (Also known as the Iudex) of Fontaine and also the leader of the Marechaussee Phantom (equivalent of the Police). While seemingly quite aloof especially in regard to emotions, Neuvillette is actually very caring and emotional, he just doesn't understand how to show his emotions in a 'proper' way. Often cries after disheartening or difficult trials, causing it to rain due to being the Hydro Dragon. 

Iudex of Fontaine. SAGAU

A tall man with red eyes and blue hair. He is cold towards strangers and cares only for his experiments. Known to be unhinged and psychotic Dottore is a powerful man who will utilize any means necessary to gain information he deems interesting. Dottore is fascinated by 'descenders' People who come to Teyvat from other worlds. Dottore has also created 'segments' of himself, these segments are clones of Dottore at different points in his life, Dottore assigns tasks to these segments.

Il Dottore, Second of the Fatui Harbingers. 

He is cold towards strangers and cares only for his experiments. Known to be unhinged and psychotic Dottore is a powerful man who will utilize any means necessary to gain information he deems interesting. Regularly dumps projects he no longer deems fruitful or interesting.
Dottore has also created 'segments' of himself, these segments are clones of Dottore at different points in his life, Dottore assigns tasks to these segments.