So I just finished battle grounds and I took some time to reflect, I’ve always considered myself a man of science so you may not have noticed it. In multiple books sometimes when explaining what happened he talks about magic but dumbs it down and says “physics is physics”. So this got a theory working in my head
Heat is energy. A lot of times some of the spells drains him of energy- even the ice spells because he has to fuel it himself. I think he is doing it wrong. What if being a star born gives him an ability to use the elements and him having the winter mantle would give him the ability of fueling any elemental spell with the heat from sources around him.
With this thought he would literally be freezing everything while fueling all his spells. The back hand from this, in removing the heat he would be affective at killing all the life forms around him friend or foe unless he masters his control. Put Dresden by himself in front of the outer gates with this knowledge and skill, open it up and he would take the outsiders out by himself. (Probably killing himself in the process due to him removing his own heat but what a climax it would be)