Spirit Warrior Badge
How to Get
Earn the Spirit Warrior accomplishment badge by putting an end to the battle between the Banished Pantheon and the Circle of Thorns. The mission is given by Cain Royce, Dr. Cheng, Oliver Haak, Piper Irving, Josef Keller,and Andrea Mitchell and described as Stop both groups of mystic madmen.
Apparently, none of the contacts for Spirit Warrior will offer the mission until level 22, even if you go through all their other missions first.
As a Flashback mission, you must complete "Stop the Mystic Madmen" which gives the mission "Defeat all villains in sewer" in the Keeper of Peace (Level 20-24) section.