With this build you can have allot of defance and also help you team mates out with the aura's and it also helps you out because each aura you get to lvl 3 gives you 40 extra magic power.
There are only 3 good aura's and the rest isnt good at all :).
Mystical Mark : Heals 30 magical damage per second to enemies in 20 feet, good for in ares ult + stun combo's
Witch stone : -15% attack speed & -25 physical power to enemies in 30 feet, again good for team fights with ares ult.
Voidblade : -40 Physical Protection to enemies in 30 feet (some will think that this is not a aura but it is).