How good is magic pen if they dont build mr
The title says it all. Should I even get the void staff if I see no mr items? Is it worth?
Thanks for replies
10 Comments
if no one has mr then no. sorc shoes should be plenty and void staff is a 3rd-5th buy in your build depending on who your facing and what they build.
+ 
negates almost most base MR in the game. That's a net 25% damage upgrade on these targets.
Later game.. u might want to end up purchasing it and getting rid of the boots in favor of another item... Or you can keep it. Void staff got buffed to the point where now it's pretty much advised to always get it... originally it was a choice between flat pen and percent pen... Flat pen was better than percentage if the enemy built no mr, currently tho, they provide pretty much the same stats. Getting both will give you pretty much true damage on all ur casts, if not bonus damage. Percentage mpen applies before flat mpen, so the 40% decrease will apply first, then the flat pen... The lowest MR at lvl 1 is like 30... the highest at lvl 18 is 53.4... Morello gives 15 flat, sorcs gives 18 flat, Void will give you 12 (against the 30 mr) and 21 (against the 53.4)... MR scales however, so after a certain point if you dont get both flat and %, then % is a better buy. [strictly in regards to percentage vs flat pen... other factors such as what else each item offers should be taken into consideration]
Soooooo, it kinda comes down to how you want to build..not just those items in isolation...if you opt out of buying morello in favor of getting liandry's and void it should be fine, if not better, in certain matchups.
Every champion has innate magic resistance. Magic penetration does get you more damage regardless of what items they build.
I wouldn't recommend Void Staff unless they're building MR because the unique passive on it doesn't get nearly as much value unless they've built for it. If you've got , it would probably be better to use that gold to buy 
or 
or 
Long story short......
percentage pen 
is a bad purchase BUT
flat pen is a very good purchase.
There are 2 types of magic pen.
- percentage pen (eg. void staff)
- Flat pen (eg. sorcerers boots)
IF THE ENEMY HAS 20 MR
subtracts 40% ....which = 12 MR remaining
reduces 18.......... which = 2 MR remaining
So at low MR gives more damage than making it a bad purchase
If they have any MR, yes. If not, No. (Keep in mind MR can come from sejuani passive, garen W, etc not just items)
Extremly good, because magic pen is % so it will always matter and if the target you hit has a higher MR you will ignore more of his MR unlike Lethality that is "flat" armor pen.
+15 pen is equal to a blasting wand when someone has base resistances. That falls off significantly as they stack MR. % is better when they do.