Friend Coltus was a Mechanist who was in charge of the workshop in the basement of the Mechanist Seminary in Eastport. When Karras realized that the Builder's Children could be completely immobilized by water entering their boilers, he gave Coltus the task of devising a way to prevent this from happening.
Friend Coltus also wrote a note explaining how to create wax impressions of various items for the purpose of making duplicates.