Couple of questions.

1) What is 'Holy Darkness'? Or other 'Holy' elements, for example?
2) If a Darkness user draws from darkness, then does his absorption create light? And does a Light user create darkness when they do the same?
3) If the answer to 2 is yes, then could a light and dark user together form a sort of super-battery?
4) Could 2 people of the same element have different powers based on their speciality?