Penetration: A Great Investment

K54·Aug 25, 2015·2 votes·896 views

My mage rune page consist of +20 magic penetration with +27 armor at level 18. The fact that are in all my builds, I end up with 50 magic penetration after ignoring 41% (including the 6% from masteries).

The most magic resist in a tank is . With that said, at level 18, tank has 210.4 magic resist with +27 mr from glyphs.

You're ignoring 41% of that mr then penetrating 50, that leaves the tank with 74.136, if you're using a melee APC etc, you can add a to the mix bringing mr to 54.136

Against any opponent that doesn't have magic resist (base is either going to be 53.4 or 30 at level 18 depending on the champ), their mr will be negative, which multiplies magic damage against them from x1.5 to x2 which is equivalent to an AD champ with 100% critical strikes.

When using I go then full tank for 86% to 100% armor penetration, add in the +20 armor pen runes and every champ (even if their build is ) will have a negative armor value which amplifies damage. Who needs critical strikes?

14 Comments

IllllllIIIIlllllAug 25, 20152 votes

magic resist can't go negative. but I agree, magic penetration is a heavily underestimated stat. I get sorc shoes second item and almost always opt for void staff instead of rabadons (did the math here, on most champs you would need 300 ap before rabadon for it be better against someone who doesn't build mr).

K54Aug 25, 20151 votes

That negative magic resist was pertaining to having item 3001 which is - 20 magic resist, which can bring mr to negative. But it's rare that I actually build one though, only being an option for me during early laning phase if I need some extra MR against lane opponent. Basically, it's my AP equivalent to rushing a item 3155

For increased magic pen I've also considered item 3091 but after giving it more thought, as an APC, you shouldn't be engaged long enough to take full advantage of this item. Though I have used it on Fizz Jax before, but in both cases the enemy team had a full AP comp.

kynan123Aug 25, 20152 votes

( ͡° ͜ʖ ͡°) P E N E T R A T I O N ( ͡° ͜ʖ ͡°)

IonianAug 25, 20151 votes

Penetration cannot reduce armor/mr to a negative value. Min is 0. Also the viability of item 3001 item 3151 depends on the champion's kit. Wouldn't really build liandry on a burst mage like Ahri.

K54Aug 25, 20151 votes

Not penetration, but item 3001 -20 reduction can. As for burst mages having item 3151 , it's effective for me in team fights when I don't want to fully dive or in close battles. Been too many occasions where I've been killed by my lane opponent or ADC/APC I targeted in a team fight, to have them drop dead 2 seconds after me. It also works extremely well when I burst someone to low health then ignite them. I get frustrated when I don't secure a kill because I didn't AA 1 more time before retreating.

IpolsAug 25, 20151 votes

the MR reduction from item 3001 is applied BEFORE the penetrations, as others say, you can't amp. the magic dmg you do by making a resistence negative

K54Aug 25, 20151 votes

Really? Shows how much I actually know. Alas, I still prefer my 3 go to items.

And I'll forever stand by my "armor penetration is better than critical strikes" comment.

IpolsAug 25, 20151 votes

"forever" is a lot of time and there are a lot of different situations xD

K54Aug 25, 20151 votes

Touché, guess I should be more specific lol. My armor penetration preference is only for the champions I listed Darius MonkeyKing Renekton Trundle JarvanIV XinZhao . Unless they get reworked, my build for them will always be item 3071 item 3035 then full tank.

IpolsAug 25, 20151 votes

Yep, as far as I know Darius , MonkeyKing Renekton and JarvanIV are great with cleaver, so they can shred enemies armor for the rest of the team and they can fight 1v1 well. I'm not a fan of item 3035 tho

K54Aug 26, 20151 votes

Whisper is so beast when combined with cleaver. I love it because that itemization allows 100% Penetration.

Also, did some research and played a few custom matches, Abyssal Scepter can take MR to negative value. Same with armor pen reduction. Flat pen and % can't, but flat reduction can amplify damage by sending defense values into the negative.

I started by googling "league of legends armor penetration" which took me to the wiki before doing the 1v1 matches.

The problem is armor/magic resist reduction is useful solely by itself because it's calculated 1st. Meaning they're really only worth getting if the opponent doesn't have resistances. Because all other pen items are useless if their value is negative.

FatalHaloAug 25, 20151 votes

% Penetration becomes less effective with Flat Penetration because it applies after Flat Penetration. 200 Armor - 20 Penetration = 180 - 63 = 117 (Flat Penetration With Last Whisper) 200 Armor - 70 = 130 (With Last Whisper) The difference is 13 Armor.

K54Aug 26, 20151 votes

% Penetration is first, then flat penetration. Reduction is what's counted before %.