Mana was a sensation unbeknownst to anyone on Earth. It wasn't a type of energy that anyone there knew how to channel or use. However, that wasn't the case anymore. Ever since Luke found himself capable of tapping into an unknown source of power, Nate too was left curious as to what he could do.
Their primary reasoning behind why and how Luke could see through the dark, in reality, was because of the curse. There were only two beings cursed by Primordials, and coincidentally that was Nate and Luke. To say that their display of magical abilities was connected to this would not be a stretch.
However, it seemed like a one-time thing for Nate, whilst Luke managed to keep his ability. Luke was still able to see through the dark, however, Nate could no longer use any spells. Although calling what he did a spell wouldn't exactly be accurate. For Luke, his ability occurred naturally, he didn't require a chant or anything, it simply just happened. However, that wasn't the case for Nate.
