These look reallly interstting.. but a few questions::
1) How long do they last??
2) Can only 1 be active at a time??
3) I have heard other classes have these as well. and they work best if each class type casts one?? ( confused about this part)..
4) To buy these AA's ya need to first buy some ranks for Fundament of power, but under requirements for fundament of power it says "Towered to Spires" .. Uhh what does THAT mean??