Magic Pen and Madreds

[quote=Rudmed]So I was just wondering if the magic pen that you get from say [[void staff]] or runes perhaps affects [[Madred's Bloodrazor]] passive. Any info on this?[/quote]

[quote=Jebus McAzn]Yes. Any magic damage you deal will be affected by any magic penetration you have. This is why it's not uncommon for some Warwick to build Sorcerer's Shoes, because they may have gotten Bloodrazor and Wit's End, for example.[/quote]

[quote=Searz]It's magic damage. Penetration affects all sources of damage. This is why I get MBR+Void Staff on Kog'Maw.[/quote]