Cain had pondered about the true nature of the {Burning Spirit} since he had discovered it...
The entirety of the skill could be summarized with a few words. By igniting the latent ability of an element with the host's body, certain special traits are granted. However, it was a double-edged sword.
Flame elemental mana boosted his attack power, but reduced his defenses in turn. Metal elemental mana boosted his defenses, but reduced his movement speed, and so on...
The abilities and 'disabilities' of each elemental enchantment were still bound by reason. Fire was the element of destruction, but everything it possessed would be left brittle, like the transformation of a blood of wood to ash, or the melting of a metal rod to slag.
Metal is the element of protection and warfare. Shields, swords, armor... They are all created with metal. However, metal had the unique property of being heavy in exchange for its defensive property.