unless you mass AP, I saw someone kill a yi that had full health at level 15 with a double bomb. so they do hurt alot, dependng on your build anyways.
Lets do the math on this.
A double bomb has a damage of 660 and an AP ratio of 1.8
A lvl 15 yi has 1734 health and 48,75 magic resist. At no magic pen he has 2579,325 effective health, which means a zilean would need 1066 AP
With sorcs, yi would have 28,75 resist, and his effective health at 2232,525. Zil would need 873 AP.
If a Zil also has a haunting guise, yi would have 8,75 resist, and 1885,725 effective health, Zil would need 681 AP
If he also had all magic pen reds, yi would have no resist, and Zil would need 597 AP
So,a Zil would need some serious stuff to one shot a yi. And I never realized before that 20 Mpen would be about 200 AP and that Mpen runes would come out at a bit less than 100 AP for a Zil, wow. I seriously need to put a haunting guise earlier, and drop my cdr boot shenanigans in my build, makes
a deathcap anything look like crap with cost effectiveness. And Im suprised the difference between full Mpen and standard resist is only 0.25.
The effectiveness of Mpen goes higher, the higher a persons health is. Meaning it might not be as good early game, but an Ashe at lvl 18 has 1781 health which means its similar to a lvl 15 yi and still almost as good as a freaking deathcap even against a squishy. Now, imagine it on a moronic Cho who stacks health.
It makes me wonder why people have so much trouble against tank teams.