League of Legends (LoL) Item: Void Staff

This is not correct as if it is multiplicative it would be 44.75% magic penetration per the math below.

You would do 35 + ((100% x 35) x 15%) = 44.75%

No, it hasn't. That's what percent magic pen is. It was simply reworded to be easier to understand for people who have no idea what "magic penetration" is. A tooltip update is in order, but the item still works the same way.

Would someone please change this to reflect the changes?

The passive *HAS CHANGED*. It is no longer percent magic pen; before all calculations, you ignore 35%, rounded, of your opponents' magic resistance, then scaling and calculations are applied to the damage.

does this increase magic damage from items like: malady, wits ends?

The new Season 3 changes to how %/flat magic pen is applyed changed this from an anti-tank situational item to a crazy carry one.

%Mpen is only different from flat Mpen in that it scales with their MR. It doesn't decrease their MR, it ignores it. They just ignore different amounts. Fiddle's passive is an MR reduction, Malady is an MR reduction, and Abyssal Scepter is an MR reduction.

I like this item. Pricy but worth it, especially with shredding stuff such as fiddle, soraka, or malady, = ouch

So now eo' Mpen reduces armor this is what I read right?
"It's calculated by reducing your enemies armor"
Ahuehuehue just has to point that out.

Uh no Drain...

That's not how %Pen works lol...

It's calculated by reducing your enemies armor, not increasing your own Magic Penetration.