Related Clues:

• One making alterations to one's character in Luther, for instance
• Luther, for instance, the one working with anagrams perhaps?
• Extremely resolute one-time agent of change
• On the subject of past crusader, perhaps
• Case of remarkable one-time revolutionary
• E.g., Martin Luther King back from service late
• Advocate of change
• Biblical teaching by old Luther, for one
• One undertaking progressive changes