Decades ago, the Asgard people hatched a plan called "Wild Warrior" to strengthen their enforcement. This plan was to train inhumanly powerful soldiers. Because of the high cost of training and keeping musicians, they were rare on the battlefield. Most times, a small battalion might not even have one musician. Even using one musician on the field as reinforcement was too much of a luxury. The general would feel immense pain if even one was lost. That was why hope was usually on regular soldiers.
And so, someone thought of a compromise: choose soldiers that had a musician’s talent and train them. They did not need to well-rounded like a proper musician. They only had to be experts in chosen "war hymns." The main goal was not to kill the enemy, but to strengthen themselves and their comrades.