Bloody Painter is the name of an online creepypasta following the life of Helen Otis. Otis is canonically around 26 years old, but age will fluctuate within the comics. In his story, he is a college student who just lost his best and only friend; later in the year, he kills several people on his dorm floor and is deemed mentally unwell in court. He is in and out of the mental hospital, but continues to murder pedestrians, using their bodies as art supplies. For more information on Bloody Painter, here is a wiki page linked below:

https://creepypastafiles.fandom.com/wiki/Bloody_Painter

Ideally, his voice would be calm, polite, and warm. He won't have a lot of words to say, I imagine him to be very quiet and reserved.