The ExtremesThe problem is that in every extreme situation, they will be outclassed by either Insight (pure magic penetration) or Desolation (pure armor penetration).
In the extreme where you do no physical damage, Insight is better.
In the extreme where you do no magic damage, Desolation is better.
In the extreme where your target has lots of armor, Insight is better.*
In the extreme where your target has lots of magic resist, Desolation is better.*
*This is not a mistake. Armor penetration is best against low-armor targets.
The Happy MediumThis means that there will be a happy medium where Destruction wins out. Where is it?
The important factors are:
- What is your ratio of physical : magic damage?
- How much armor and magic penetration do you get from other sources?
- How many quintessences are you using for penetration?
At the bottom of this post is a link to a Google document that you can view or download. You'll enter the factors, and see which penetration runes are best against various targets. Remember that if the enemies build too much armor, you'll wish you had magic penetration, and if the enemies build too much magic resist, you'll wish you had armor penetration.
|The front of the sheet|
- Your ratio of Physical:Magic damage
- The number of these runes you will use (usually 3, or 7.5 if you are using the marks too, since marks are half of quints).
- Your other sources of flat magic pen (maybe items you plan to have).
- Your other sources of flat armor pen (don't forget the mastery!).
- Your percentage magic pen (void staff, mastery).
- Your percentage magic pen (last whisper, mastery).
It will show you a pretty grid! The rows and columns are labeled with your target's magic resistance and armor. So, if you go way to the right on the grid, you are looking at very very armored enemies, and toward the bottom is very very magic resistant enemies. The pretty green area in the middle is the sweet spot for the Destruction runes. Toward the right, against lots of armor, it shows a blue m for magic penetration: you want Insight runes. Toward the bottom, against lots of magic resistance, it shows a yellow a for armor penetration: you want Desolation runes for them.
Early-Game ShyvanaFor a champion who does about 7 physical damage for every 10 magic damage (my estimate of Shyvana's damage), the ratio is 0.7.
When I play Shyvana I want to do some early-game counterjungling, so I tend to go up against the enemy jungler, who has about 55 Armor and 35 MR. Look! That whole area is green! So I use Destruction quints.
Late-Game ShyvanaLate-game, you might be hitting squishies with 100 armor and 50 magic resist, or bruisers with 200 armor and 150 magic resist. What then?
|Late-game, you might feel torn between Destruction and Insight.|
Destruction is on the borderline late game, and it's the best early. So I run the Destruction and feel good about it.
How Much Does It Matter?The last sheet displays how important it is to choose the best runes: it tells you what percentage damage boost you get from choosing properly. Specifically, it is how much the best runes outperform the second-best runes. Remember that Destruction are always either best or second-best.
Toward the upper-right and lower-left corners, this shows how much better the single-type penetration runes are than the mixed penetration runes. As the damage boost reaches 0, the tiles fade to black -- these are the borderlines where Destruction runes are even with one of Insight or Desolation.
|The Percent Benefit sheet|
This means there is a reasonable range where the Destruction runes are the best runes, and a huge range where choosing anything else is only at most 0.25% better than Destruction.
Link To The SpreadsheetIf you'd like to look at the spreadsheet, it is published here.
To download your own copy to excel (the colors don't quite work but the rest does), go here.