Question about Magic Pen

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Jshellz

Junior Member

09-14-2011

Is it worth it to get magic penetration when your opponents have no magic resist items? What i mean is, if the opposing team all went for full damage output (not the highest of skill levels), should an ap caster get a void staff, or would a more ap heavy item be better? Thanks!


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Fluffy1

Senior Member

09-14-2011

resist give them 1% effective hp, 10 MR is still a 9-10% damage reduction, if they arent getting MR get some flat pen(ideally sorc boots or abyssal scepter) to drop them to 0 MR to do full damage, if they have any MR items your prob gonna want the void stave since countering even 60 MR to make it worth the time with flat pen is stupidly expensive.


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Ellye

Senior Member

09-14-2011

If the enemy team has basically zero magic resist items, all you need is a Sorcerer's Shoes or Abyssal Scepter or Haunting Guise.
Assuming you have Magic Penetration runes.


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Snaketeeth01

Senior Member

09-14-2011

Also take into consideration the caster.
Fid's for example with mpen marks, his passive, and the proper masteries he will almost take out all the enemies MR at the start of the game. This make's a little AP go a long way, which allows me to build him tankier to start with.

I find with any caster though haunting guise is a cheap early item that will at the very least help you in the lategame, until you sell it for a better item.


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Tigger Trap

Junior Member

09-14-2011

Will you do increased DMG if your sorc shoes already counter the already low MR ingame, and then you buy Void Staff? Will this make your DMG double fold or whatever?


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AngryNarwhal

Senior Member

09-14-2011

MPen Reds & Quints + Sorc Boots = ~0 MR squishies


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David Slain

Junior Member

09-14-2011

Magic Penetration will never drop your enemy's resist below 0. Magic Resist Reduction (such as Amumu's and Fiddle's passives, as well as Abyssal Scepter) will. I run a Karthus build that starts with Sorc. Boots and Haunting Guise, which, combined with runes, gives 49 flat Mpen.

The game calculates like this: Flat Magic Resistance Reduction, Flat Magic Penetration, Percent Magic Penetration.

With his wall and Abyssal Scepter, by the end of the game, my Karthus has 55 Magic Resistance Reduction, 49 Flat Magic Penetration, and 15% Magic Penetration. Even if the opposing carry buys magic resist, this is normally enough to rip right through it...

Using the above numbers, let's take a look at a battle between Ashe and Karthus:

Ashe, if she buys NO magic resist has, I think, 30 native Magic Resist. At level 18, my wall has 35 Magic Resist Reduction, and Abyssal Scepter gives 20 more.

Ashe, being a physical carry, is overconfident, and I snag her in my wall. At this point she has -25 Magic Resist (thanks to everything) and my spells calculate as such. ( 1-(-25/125) = 120% ) Which means that my AOE, which normally does 273 damage per second, does 328 damage per second, and my bomb, which does 510, now does 612. I can cast one bomb per second- ish, so my damage per second vs this very foolish Ashe is 940. My ult hits her for 1128 damage, which is just under half her health.

All these numbers are calculated based off of 650 AP- a conservative amount of AP for Karthus.

Now, same battle vs Garen- 120 Mres. It's dropped to 65 by my wall and the scepter, which gets rid of the reduction, and the Penetration gets rid of another 49, which drops it to 16, and my 15% penetration drops that to 13. Given this, you do 87% damage to him, meaning my AOE does 240 damage per second, and my bomb does 449, making it 690 damage per second.

Finally, we have Blitzcrank, who gets Banshee's Veil against me.

80 Magic Resist, to 25 by wall and scepter, then the other flat magic penetration eliminates the rest of it, but not dropping it below zero, causing my abilites to deal normal, unaltered damage. ( AOE is 510, 273, and ult for 940.

Now, if this Blitz is out of my Scepter range, or I have just died (so Abyssal Scepter doesn't work anymore) and he's still under the effects of my wall (which is why when you die with Karth, it's the FIRST spell you slam down) my Ult will work like this: 80 Magic Resist - 35 for wall - 49 flat means I still hit him for full damage. This is why Karthus works so dang well with Amumu and Fiddlesticks.

With Karth, Amumu, and Fiddle together, along with a single Abyssal (because only ONE works- UNIQUE passive, remember?) it's 35+20+35+10 = 100 Magic Resist Reduction on any target amumu hits with his melee. The number is 65 for everyone else. Basically, here's where it gets stupid. Those numbers for ashe basically go to the entire team and all three of us magic damage dealers wipe out four of the five person team and are dealing full damage to the remaining tank after about two seconds. Amumu pops his ult, Fiddle Ults in, and Karth just walks around with his AOE on and uses his wall. If someone manages to survive, Karth takes them down with his Ult, even if Karth happens to die in the process of the teamfight.

Sorry for the book. I hope this helps, and gives you an idea or two.