An explanation of Hamon (as it stands in Daybreak anyway) will go here;

As a basic primer for the time being, Hamon in the AU Setting is the weaponized use of inner 'Radiance', or 'Candle Flame'- while perpetually present, it relies on a steady pattern of breathing while actively in use, and sustaining the breathing pattern allows one to gather a store of this energy for grander techniques.

Elementally, it is best likened to 'Holy', or 'Light'- and is the natural weapon against undead, unholy, and otherwise 'dark (evil, rotted)' beings.