Why I love Glass Cannon Vel'koz
I'll use Caitlyn as an example who'll likely be around 57 Mr without any defensive items and at lvl 18. This can change from 30-107 depending on your threat level towards the ADC. Now whats extremly important is my preferred runes for Vel is +14 Mpen. This'll hurt his early game, but hyper buff his lategame. I'll tend to build Sorc boots, Liandires, Void Staff, Death Cap, Situational AP, Situational Now that means I'll be at 44 +35% Mr shred. Percent MR shred is applied before flat. This means that her Mr will reach 0. The normal equation for Mr is 100/(100+MR) So 100/(157)=.637 or 36.3% Magic reduction. Her Resistance will drop to 0 creating 1.0 or 0.0% Magic Reduction. A tank with 200 Mr will be at 86 or .538=46.2% compared to no Mpen at .333=77.7% Magic Reduction With those situational items turning into Athenes, and morellonomicon (two good items for sieging) your AP will be at 494 AP With amplification will be ~1325.15. You'll nearly one hit her. This is why I love Glass Cannon Vel'koz.