+70 Ability Power +300 Health -Grievous Wounds +15 magic penetration
This item grants some durability, decent damage, and helps counter champions that are reliant on sustain to do their jobs, so why does this item need penetration? Considering decent mage players always build Void Staff and Sorcerer Shoes (and some of them also build Liandry's) is the penetration on this item really necessary?
Could someone explain please? Because I don't understand.
Is any stat or effect on any item necessary?
Previously penetration was on 
, but it was replaced because works best against tanks while flat mpen works best against no mr targets, so they replaced flat mpen with stacking damage growth and put mpen at some random place, namely 
.
By the way, 70 ap is not "decent damage", its barely more than 
and 
. 
has more AP, 20% cdr, mana and bonus damage proc. 
gives 30 more ap, 200 more hp and 400 more mana while being 400 gold cheaper. Without mpen, it will only be viable against heavy healing team
I’m pretty sure people just buy 
and don’t upgrade it until late.
