From Portals of Phereon Wiki

A dangerous trait that continually stacks Burns on a unit and adds that to their attack power. Note that being Lava Immune does not make a unit immune to Burns. However the Heat Resistant trait will prevent Burn damage, making this incredibly powerful.

You'd think this would be the perfect trait for Lava types, but they are completely immune to Burns, not even receiving them in the first place, making this useless for them.