I need some help!

Could someone help me and give some info.
1) How does the passive Necromancer work? Does it stacks for each aura or not, so it will be 15% for 1 aura, 30% for 2 etc.
2) Same question for Guardian passive.

Thats I really need to know!
Guys, someone help me!

And I need 100% information.

Thx for help.

It says "... by auras you cast" not increased damage/cast speed "for each aura you cast", therefore you don't get additional damage/cast speed if you are affected by more than 1 aura.