The Master Guide (MG) curriculum is one of the leadership programs that the General Conference Youth Ministries Department uses to train people for youth leadership. It is the "Ph.D." of youth ministry in the field. You cannot earn your Master Guide without taking at least one Basic Staff Training (BST) course.
The Master Guide is the expert, the advisor, the promoter for Adventurers and Pathfinders. As such, MG is NOT a Pathfinder program, it is a Youth Ministry Leadership Program.