Ruprett mentioned Antoinne while drawing the route into Agrilla. In the quieter lower cells, the company finds the man himself.
Antoinne hears Ruprett but cannot see him. Grigori and Aruma watch Ruprett question him about his victims. The answers are disturbing enough that the party has no interest in adding him to the rescue.
Shadow
Antoinne says the nuns believe he has a devil inside him and fear what hanging him would release. Ruprett asks whether that is still true. Antoinne describes Shadow as having shown him how to be free.
These are statements made by Antoinne and Ruprett. They do not settle whether possession explains his crimes, or what the prison's keepers actually know. Antoinne asks again to be released. The company leaves him behind bars.