Why do I get a heat and matter debuff, when I don cast heat or matter spells?
Mythic’s philosophy behind the debuff spells is that they are meant for grouping. That is, no caster should be able to debuff their primary damage type. That is why, for example, the cold debuff spell is in the runecarving spec line, while all of our cold damage spells are in the darkness line. So, why heat and matter? Mostly for completeness. There are spells (such as the shaman DoT, bolt and DD) that cause Body damage, but you are much better off just nuking instead of debuffing damage for a shaman. Likewise, there are items that proc heat damage, or that have charges of heat-based DD spells. But those are generally not available until level 45+, and you are not likely to want to take 2 seconds to cast a debuff when the charged item is an insta-cast.