Talk:List of runes/@comment-192.223.163.6-20120328205832/@comment-77.249.233.124-20120519142906

^ With AP is applied every hit I mean every time you hit someone with a damaging spell.

What I mean is that mpen only reduces the target's effective HP. If you have 50 extra damage from AP than after 5 attacks you've dealt 250 damage from that. However mpen only reduces effective HP and thus doesn't stack up with each attack. The way I look at it you could see mpen as a certain amount of HP reduction before you calculate any damage, while AP helps you deal more of that damage.

If someone has 1K hp and 100 mres their effective HP is 2K against magic attacks (because 100 mres halves all magic damage, so it's like they have 2x their HP). So let's say you have 20 mpen that reduces their effective HP to 1800. So in total that's worth 4 attacks if you take the 50 damage from AP in the previous paragraph.

Now what I was getting at is that in most cases the damage increase AP gives is better than the effective HP reduction that mpen gives, simply because you will virtually never have enough mpen to reduce effective HP by a significant amount compared to the extra damage you can get from AP. It's nice if you can deal "true" damage to someone, but if you got no AP or damage to back that up it's no use.