Talk:Kayle/@comment-4542190-20140607223538/@comment-7620198-20140608022852

Runaan's applies on-hit, as you've said. I don't think the Runaan's hits splash, they just apply the on-hit magic damage ( Bonus Magic Damage: 20 / 30 / 40 / 50 / 60 (+ 40% AP) ).

So, here's the thing. With Runaan's, secondary targets take both the on-hit magic damage (+ 40% AP) and the splash damage (+ 40% AP). The primary target only takes the on-hit damage. With Runaan's, the secondary targets are taking 95% of your AP per hit, considering you've got a Nashor's too. This is actually mentioned on the strategy page, which is where I first learned this interesting bit of trivia. The secondary targets take more overall damage from the E than the primary. Also, the AOE shred is nothing to be scoffed at.

To put it in one sentence, it doubles her AOE autoattack damage. That's pretty huge.