wow.....
a whole crapload of work has gone into these, hopefully someday we'll be able to admit this series as an entire new element, i think it deserves it. IMO (just spewin' ideas, humor me) a viable dual element to go with this would be called "space" or "distance" or something along those lines. Fortunately opposing elements don't have to have opposing mechanics, so the main mechnic for void is quanta denial, and the mechanic for "space" would be along the lines of AoE cards, things that use and manipulate the layout of the field. Just a little world of elements fantasy of mine, but if they arent able to make a new element, then this should at least get into the "other" category.
hah, just remembered "blood", wonder what the dual element of that would be, could be divine i guess, bc blood represents mortality while divine represents...... immortality...... sort of